I present to you the HTML version of the book S.A. Bazhanov "How a radio tube works. Gain classes" Gosenergoizdat, Moscow, Leningrad 1947.

Familiarization with the history of the invention of the radio tube takes us back to 1881, when the famous inventor Thomas Edison discovered the phenomenon that later formed the basis for the operation of almost every radio tube. Engaged in experiments, the purpose of which was to improve the first electric lamps. Edison introduced a metal plate into the glass bulb of the lamp, placing it close to the incandescent carbon filament. This plate did not connect at all with the thread inside the flask (Fig. 1). The metal rod that held the plate passed through the glass to the outside. To prevent the filament from burning out, the air from the lamp bulb was pumped out. The inventor was very surprised to notice the deviation of the arrow of the electrical measuring instrument included in the conductor connecting the metal plate to the positive pole (plus) of the filament filament battery. Based on the ideas common at that time, it was impossible to expect the appearance of current in the circuit "plate - connecting wire - plus batteries", since this circuit is not closed. However, the current passed through the circuit. When the connecting wire was connected not to the plus, but to the minus of the battery, the current in the circuit of the plate stopped. Edison could not give an explanation for the discovered phenomenon, which went down in the history of the radio tube under the name of the Edison effect.

The explanation for the Edison effect was given much later, after the discovery of electrons, the smallest negative charges of electricity, by Stoie and Thomson in 1891. In 1900-1903. Richardson undertook scientific research, which resulted in experimental and theoretical confirmation of Thomson's conclusion that the hot surface of conductors emits electrons. It turned out that the method of heating the conductor is indifferent: a nail heated on burning coals emits electrons (Fig. 2) in the same way as a filament of an electric lamp heated by an electric current. The higher the temperature, the more intense the electron emission. Richardson deeply investigated electron emission and proposed formulas for calculating the number of emitted electrons. He also found that when heated to the same temperature, different conductors emit electrons to varying degrees, which was attributed to the structural properties of these conductors, i.e., the features of their internal structure. Cesium, sodium, thorium and some other metals are characterized by increased emission properties. This was subsequently used in the design of intense electron emitters.

However, the establishment of the mere fact of the existence of electron emission from the surface of incandescent conductors (such emission is called thermionic or thermionic) does not yet explain the appearance of current in the circuit of the Edison lamp plate. But everything becomes completely clear if we recall two circumstances: 1) opposite electric charges tend to attract, and the same ones tend to repel; 2) the flow of electrons forms an electric current of greater strength, the more electrons move (Fig. 3). The plate, connected to the plus of the lamp's incandescent battery, is positively charged and therefore attracts electrons, the charge of which is negative. Thus, the apparent open circuit inside the lamp is closed and an electric current is established in the circuit, which passes through the electrical measuring device. We deviate the arrow of the device.

If the plate is charged negatively with respect to the filament (this is exactly what happens when it is connected to the minus of the incandescent battery), then it will repel electrons from itself. Although the hot filament will still emit electrons, they will not hit the plate. No current will appear in the circuit of the plate, and the arrow of the device will show zero (Fig. 4). The hot filament will be surrounded on all sides by a large number of electrons continuously emitted by the filament and again returning to it. This "electron cloud" around the filament creates a negative space charge that prevents electrons from escaping from the filament. It is possible to eliminate the space charge (“dissolve the electron cloud”) by the action of a positively charged plate. As the positive charge increases, the electron-attracting force of the plate increases, more and more electrons leave the "cloud", heading towards the plate. The spatial negative charge around the filament decreases. The current in the circuit of the plate increases, the arrow of the device deviates along the scale towards large readings. Thus, the current about the circuit of the plate can be changed by changing the positive charge of the plate. This is the second opportunity to increase the current. We already know about the first possibility: the higher the temperature of the hot filament, the stronger the emission. However, it is possible to overestimate the temperature of the filament only up to certain limits, after which there is a danger of the filament burning out.

But the increase in the positive charge on the plate also has limits. The stronger this charge, the greater the speed of electrons flying to the plate. It turns out the electron bombardment of the plate. Although the impact energy of each electron is small, there are many electrons, and from impacts the plate can become very hot and even melt.

An increase in the positive charge of the plate is achieved by including a battery with a high voltage in its circuit, and the plus of the battery is connected to the plate, and the minus to the thread (to the positive pole of the incandescent battery, Fig. 5). Leaving the temperature of the filament unchanged, i.e., maintaining the filament voltage unchanged, it is possible to determine the nature of the change in the current in the circuit of the plate, depending on the change in the voltage of the "plate" battery. It is customary to express this dependence graphically by constructing a line that smoothly connects the points corresponding to the instrument readings. On the horizontal axis from left to right, the increasing values ​​of the positive voltage on the plate are usually plotted, and not on the vertical axis, from the bottom up - the increasing values ​​of the current in the circuit of the plate. The resulting graph (characteristic) suggests that the dependence of current on voltage is proportional only within limited limits. As the voltage on the plate increases, the current in its circuit increases first slowly, then faster and then evenly (the linear section of the graph). Finally, there comes a moment when the increase in current stops. This saturation current cannot be increased: all the electrons emitted by the filament are completely used up. The "electronic cloud" has disappeared. The circuit of the lamp plate has the property of one-way transmission of electric current. This one-sidedness is determined by the fact that electrons ("current carriers") can pass in such a lamp in only one direction: from the hot filament to the plate. John Fleming when he in 1904 was engaged in experiments on receiving wireless telegraph signals, a detector-device with one-sided current transmission was needed. Fleming used a vacuum tube as a detector.

So the Edison effect was first applied in practice in radio engineering. The technique was enriched with a new achievement - the "electric valve". It is interesting to compare two circuits: Fleming's receiver circuit, published in 1905, and the modern circuit of the simplest receiver with a crystal detector. These schemes essentially differ little from one another. The role of the detector in Fleming's scheme was performed by an "electric valve" (valve). It was this "valve" that was the first and simplest radio tube (Fig. 6). Since the “valve” passes current only with a positive voltage on the plate, and the electrodes connected to the plus of the current sources are called anodes, then exactly what name is given to the plate, no matter what shape (cylindrical, prismatic, flat) it is given. The thread connected to the minus of the anode battery (the “plate battery”, as we called it earlier) is called the cathode. Fleming's "valves" are widely used to this day, they do not have other names. Every modern AC-powered radio receiver has a device that converts the AC current into the DC current needed by the receiver. This transformation is carried out by means of "valves" called kenotrons. The device of the kenotron is in principle exactly the same as the device in which Edison first observed the phenomenon of thermionic emission: a bulb from which air is pumped out, an anode and a cathode heated by an electric current. The kenotron, passing the current in only one direction, converts the alternating current (i.e., the current that alternately changes the direction of its passage) into a direct current, passing all the time in one direction. The process of converting alternating current to direct current by kenotrons is called rectification, which should, apparently, be explained by a formal sign: the alternating current graph usually has the shape of a wave (sinusoid), while the direct current graph is a straight line. It turns out, as it were, a “straightening” of the wavy graph into a straight one (Fig. 7). A complete device used for rectification is called a rectifier. The general name for all radio tubes with two electrodes - an anode and a cathode (although the thread has two leads from the bulb, but it is one electrode) is a two-electrode lamp or, for short, a diode. Diodes are used not only in rectifiers, but also in the radio receivers themselves, where they perform functions related directly to the reception of radio signals. Such a diode, in particular, is a lamp of the 6X6 type, in which two diodes independent of each other are placed in a common bulb (such lamps are called double diodes or double diodes). Kenotrons often have not one, but two anodes, which is explained by the features of the rectifier circuit. The anodes are either located near the common cathode along the filament, or each anode surrounds a separate cathode. An example of a single-anode kenotron is a lamp of the VO-230 type, and two-anode ones are lamps 2-V-400, 5Ts4S, VO-188, etc. A graph expressing the dependence of the anode current of the diode on the voltage at the anode is called the characteristic of the diode.

In 1906, Lv de Forest placed a third electrode in the form of a wire mesh in the space between the cathode and anode. So a three-electrode lamp (triode) was created - the prototype of almost all modern radio tubes. The name "grid" has been preserved for the third electrode to this day, although at present it does not always have the form of a grid. Inside the lamp, the grid is not connected to any other electrode. The conductor from the grid is brought out of the flask. By including a grid battery between the output conductor of the grid and the output of the cathode (filament), it is possible to charge the grid positively or negatively relative to the cathode, depending on the polarity of the battery.

When the positive pole (plus) of the grid battery is connected to the grid, and the negative pole (minus) to the cathode, the grid acquires a positive charge and the greater the greater the voltage of the battery. When the battery is turned on again, the grid is charged negatively. If the grid conductor is directly connected to the cathode (with some kind of filament lead), then the grid acquires the same potential as the cathode has (more precisely, which has the point of the filament circuit to which the grid is connected). We can assume that in this case the grid receives a zero potential relative to the cathode, i.e., the grid charge is equal to zero. Being under zero voltage, the grid has almost no effect on the flow of electrons rushing to the anode (Fig. 8). Most of them pass through the holes of the grid (the ratio between the size of electrons and the holes of the grid is approximately the same as between the size of a person and the distances between celestial bodies), but some of the electrons can still get on the grid. From here, these electrons will go to the cathode along the conductor, forming a grid current.

Having received a charge of one sign or another (plus or minus), the grid begins to actively interfere with the electronic processes inside the lamp. When the charge is negative, the grid tends to repel electrons that have the same charge. And since the grid is located on the path of electrons from the cathode to the anode, the repulsion of the grid will return the electrons back to the cathode (Fig. 9). If you gradually increase the negative charge of the grid, then the repulsive effect will increase, as a result of which, with a constant positive voltage at the anode and a constant filament filament voltage, the anode will receive an ever smaller number of electrons. In other words, the anode current will decrease. At a certain value of the negative charge on the grid, the anode current may even stop completely - all the electrons will be returned back to the cathode, despite the fact that the anode has a positive charge. The grid with its charge will overcome the action of the anode charge. And since the grid is closer to the cathode than the anode, its influence on the electron flow is much stronger. It is enough to change only a little the voltage on the grid, so that the anode current changes very much. The same change in the anode current can, of course, be obtained by changing the anode voltage, leaving the voltage on the grid unchanged. However, to obtain exactly the same current change in the anode circuit, a significant change in the anode voltage would be required. In modern triodes, a change in the grid voltage by one or two volts causes the same change in the anode current as a change in the anode voltage by tens and even hundreds of volts.

A positively charged grid does not repel, but attracts electrons to itself, thereby accelerating their run (Fig. 10). If we gradually increase the positive voltage on the grid, starting from zero, we can observe the following. At first, the grid will, as it were, help the anode: flying out of the hot cathode, the electrons will experience a stronger accelerating effect. The bulk of the electrons, heading towards the anode, by inertia will fly through the holes in the grid and fall into the "grid space" in the field of the amplified anode voltage. These electrons will go to the anode. But some of the electrons fall directly on the grid and form a grid current. Then, as the positive charge of the grid increases, the grid current will increase, i.e., an increasing number of electrons from the total electron flow will be retained by the grid. But the anode current will also increase, as the electron velocities increase. Finally, all emission will be completely used, the space charge around the cathode will be destroyed, and the anode current will stop increasing. Saturation will occur, the emitted electrons will be divided between the anode and the grid, and most of them will fall on the anode. If the positive voltage on the grid is increased even more, this will lead to an increase in the grid current, but only due to a decrease in the anode current: the grid will intercept an increasing number of electrons from their stream heading to the anode. At very high positive voltages on the grid (greater than the voltage at the anode), the grid current can even exceed the anode current, the grid can “intercept” all the electrons from the anode. The anode current will decrease to zero, and the grid current will increase to a maximum equal to the lamp saturation current. All electrons emitted by the filament hit the grid.

The characteristic properties of three-electrode lamps are clearly displayed by a graph of the dependence of the anode current on the voltage on the grid with a constant positive voltage on the anode. This graph is called the characteristics and lamps (Fig. 11). At a certain negative voltage on the grid, the anode current stops completely; this moment is marked on the graph by the confluence of the lower end of the characteristic with the horizontal axis, along which the stress values ​​on the grid are plotted. At this point, the lamp is "locked": all the electrons are returned by the grid back to the cathode. The grid overcomes the action of the anode. The anode current is zero. With a decrease in the negative charge of the grid (movement along the horizontal axis to the right), the lamp “unlocks”: an anode current appears, at first weak, and then increasing more and more rapidly. The graph rushes up, moving away from the horizontal axis. The moment when the grid charge is brought to zero is marked on the graph by the intersection of the characteristic with the vertical axis, along which the values ​​of the anode current are plotted upwards from zero. We begin to gradually increase the positive charge on the grid, as a result of which the anode current continues to increase and, finally, reaches its maximum value (saturation current), at which the characteristic bends and then becomes almost horizontal. All electron emission is fully utilized. A further increase in the positive charge of the grid will only lead to a redistribution of the electron flow - an increasing number of electrons will be retained by the grid and, accordingly, a smaller number of them will fall on the anode. Typically, radio tubes do not operate at such high positive voltages on the grid, and therefore the dotted section of the anode current characteristic can be ignored. Pay attention to the characteristic starting at the point of intersection of the axes. This is a characteristic of the grid current. A negatively charged grid does not attract electrons to itself, and the grid current is zero. With an increase in the positive voltage on the grid, the current in its circuit, as the graph shows, increases. So far, we have assumed a constant voltage at the anode. But with an increase in this voltage, the anode current increases, and with a decrease, it decreases. This leads to the need to take and, therefore, draw not one characteristic, but several - one for each selected value of the anode voltage. Thus, a family of characteristics is obtained (Fig. 12), in which the characteristics corresponding to higher anode voltages are located higher, to the left. For most of their length, the characteristics are parallel. So, there are two possibilities to influence the value of the anode current: by changing the voltage on the grid and by changing the voltage at the anode. The first possibility requires fewer changes, since the grid is closer to the cathode than the anode, and therefore changes in its potential affect the electron current much more strongly. A numerical coefficient indicating how many times the influence of the grid under exactly the same conditions is greater than the influence of the anode is called the lamp amplification factor. Suppose that an increase in the anode voltage by 20V has the same effect on the anode current as a change in the grid voltage by only 1V. This means that the design of this lamp is such that in it the influence of the grid on the anode current is 20 times stronger than the influence of the anode, i.e., the amplification factor of the lamp is 20. Knowing the magnitude of the amplification factor, one can evaluate the amplifying properties of the lamp, determine how many times stronger oscillations of the electric current will arise in the anode circuit if relatively weak electric oscillations are brought to the grid. Only the introduction of a grid into the lamp made it possible to create a device that amplifies electrical oscillatory currents: the diodes we considered earlier do not possess amplifying properties. The steepness (slope) of the characteristic is essential when evaluating the properties of a lamp. A lamp with a large steepness is very sensitive to changes in the voltage on the grid: it is enough to change the grid voltage to a very small extent, so that the anode current changes significantly. The steepness is quantified by the magnitude of the change in the anode current in milliamps when the grid voltage changes by 1 volt.

The cathode in a radio tube is a thin metal wire (filament) heated by a current. If the heating of such a filament is carried out with direct current, then the emission of electrons will be strictly constant. But almost all modern broadcasting receivers are powered by alternating current, and the filament cannot be heated with such a current, since the electron emission will change, “pulsate”. An alternating current hum will be heard from the loudspeaker - an unpleasant buzz that interferes with listening to the program. Of course, it would be possible to first rectify the alternating current with the help of a diode, turn it into a direct current, as is done to power the anode circuits - we have already talked about this. But a much simpler and more efficient method has been found that allows direct alternating current to be used to heat the cathode. A tungsten filament - a heater - is placed in the channels of a thin and long porcelain cylinder. The thread is heated by an alternating current, and its heat is transferred to a porcelain cylinder and a nickel “case” put on top of it (Fig. 13), on the outer surface of which a thin layer of alkali metal oxides (strontium, barium, cesium, etc.) is deposited. These oxides are characterized by high emissivity even at relatively low temperatures (about 600 degrees). It is this layer of oxides that is the source of electrons, i.e., the actual cathode. The output of the cathode from the flask is attached to a nickel “case”, and there is no electrical connection between the cathode and the heated filament. The whole heated device has a relatively large mass, which does not have time to lose heat during rapid changes in alternating current. Due to this, the emission is strictly constant and no background is heard in the receiver. But the thermal inertia of the cathode of the lamps in the receiver is the reason that the included receiver does not start working immediately, but only when the cathodes are heated. The grids in modern lamps most often look like wire spirals: “dense grid” - the coils of the spirals are located closer to each other, “sparse grid” - the distances between the turns are increased. The thicker the grid, the greater its influence on the electron flow, ceteris paribus, the greater the gain of the lamp.

In 1913, Langmuir increased the number of electrodes in the lamp to four, proposing to introduce another grid into the space between the cathode and the grid (Fig. 14). So the first tetrode was created - a four-electrode lamp with two grids, an anode and a cathode. The grid that Langmuir placed closer to the cathode is called the cathode grid, and the "old" grid was called the control grid, since the cathode grid plays only an auxiliary role. With its small positive voltage, received from part of the anode battery, the cathode grid accelerates the flow of electrons to the anode (hence the other name of the grid - accelerating), "dissolving" the electron cloud around the cathode. This made it possible to use the lamp even at relatively low voltages at the anode. At one time, our industry produced a two-grid lamp of the MDS (or ST-6) type, in the passport of which it was indicated: the working anode voltage was 8-20V. The most common at that time lamps of the Micro type (PT-2) usually operated at much higher voltages - about 100 V. However, cathode grid lamps did not gain popularity, as even more advanced lamps were soon proposed instead of them. In addition, "two grids" had a significant drawback: a positively charged cathode grid took a very large number of electrons from the total flow, which is tantamount to their useless expenditure. Although the opportunity to work with low anode voltages was tempting, this was opposed by a large waste of current - there was no tangible benefit. But the introduction of the second grid served as a signal for the designers of radio tubes: the "era" of multi-electrode lamps had begun.

In shielded lamps, one unpleasant phenomenon had to be faced. The fact is that electrons hitting the surface of the anode can knock out the so-called secondary electrons from it. These are, by their nature, the same electrons, only released from a metal surface not by heating (as from a cathode), but by electron bombardment. One bombarding electrode can knock out several secondary electrons. It turns out that the anode itself turns into a source of electrons (Fig. 16). A positively charged screening grid is located near the anode, and secondary electrons, flying out at low speeds, can be attracted to this grid if at any moment the voltage on the grid turns out to be greater than the voltage on the anode. This is exactly what happens when a shielded tube is used in the final low frequency amplification stage. Rushing to the screening grid, the secondary electrons set up a reverse current in the lamp, and the operation of the lamp is completely disrupted. This unpleasant phenomenon is called the dinatron effect. But there is a way to combat this phenomenon. In 1929 the first lamps with five electrodes appeared, of which two are the anode and cathode, and the remaining three are grids. According to the number of electrodes, these lamps are called pentodes. The third grid is placed in the space between the shielding grid and the anode, i.e., it is closest to the anode. It connects directly to the cathode and therefore has the same potential as the cathode, i.e. negative with respect to the anode. Due to this, the grid returns the secondary electrons back to the anode and thus prevents the dynatron effect. Hence the name of this grid - protective or anti-dinatron. In many of their qualities, pentodes are superior to triodes. They are used to amplify the voltage of high and low frequencies and work great in the final stages.

The increase in the number of grids in the lamp did not stop at the pentode. The series "diode" - "triode" - "tetrode" - "pentode" was replenished with one more representative of the tube family - the hexode. This is a lamp with six electrodes, of which four are grids (Fig. 17). It is used in high-frequency amplification and frequency conversion stages in superheterodyne receivers. Usually, the strength of the radio signals coming to the antenna, especially at short waves, varies over a very wide range. The signals either increase or fade quickly (the phenomenon of fading - fading). The hexode, on the other hand, is designed in such a way that it automatically quickly changes the gain: it amplifies weak signals to a greater extent, and strong ones to a lesser extent. As a result, audibility is leveled and maintained at approximately the same level. The automaticity of the action is achieved by changing the potentials on the grids in time with the change in the strength of the received signals. Such a hexode is called a fading hexode. In conventional receivers, such gain control also takes place, but is carried out by means of pentodes with an elongated lower part of the characteristic, where the slope has a smoothly changing value. Such pentodes are called
"cooking".

The second category of hexodes are mixing hexodes. In superheterodyne receivers, the received signal is first reduced in frequency and then amplified. This reduction or frequency conversion can also be done with triodes, as has been done previously. But mixing hexodes perform this function more rationally. In our practice of broadcast reception, other lamps with even more grids are used to perform this function. These are pentagrids (five-grid lamps) or, as they are otherwise called, heptodes (seven-electrode lamps). Lamps of type 6A8 and 6L7 belong to this category of lamps. For frequency conversion in superheterodyne receivers, a six-grid lamp (eight electrodes) - an octode is also used. Unlike a pentagrid, an octode is, as it were, a combination of a triode with a pentode (whereas a pentagrid is a triode with a tetrode). Appearing later than the pentagrid, the octode is superior in its qualities to its predecessor.

But lamps have been developing not only in the “grid direction” in recent years. We have already spoken about the placement of two "electric valves" in a common flask, referring to the device of a double diode of the 6X6 type. Combinations such as diode-triode, double triodes, double diode-triodes (DDT), double diode-pentodes (DDP), triode-hexodes, etc. are now widely used. For the most part, such combined lamps have a common cathode. The operation of one lamp is likened to the operation of several simpler ones. For example, a 6H7 lamp is a double triode - two separate triodes in a common bulb, kind of twins. This lamp successfully replaces two triode lamps and can be used either in a two-stage resistance amplifier or in a push-pull circuit (push-pull), for which it is actually intended. After detection, which is done in superheterodyne receivers, usually by means of diodes, it is necessary to perform amplification. For this purpose, an amplifying triode is now placed in a common flask with a detecting diode: this is how diode-triodes appeared. In superheterodyne receivers for automatic volume control (AGC) it is necessary to receive a direct current, the value of which would change in time with the strength of the received signals. For these purposes, it would be possible to use a separate diode, but it turned out to be possible to place it in a diode-triode flask. So three lamps were placed in one lamp at once: two diodes and a triode, and the lamp was called a double diode-triode. In the same way, a diode-pentode, a triode-hexode, etc. arose. A lamp of the 6L6 type stands somewhat apart from other lamps. This is a very interesting lamp: there is no one electrode in it, but it is, as it were, implied. On the one hand, this lamp is an obvious tetrode, since it has only four electrodes: a cathode, an anode and two grids, of which one is control and the other is shielding. But, on the other hand, 6L6 is a pentode, because it has all its properties and very positive features. The role of the protective grid, mandatory for the pentode, in the 6L6 lamp is performed by ... an empty space, an artificially created zone located between the anode and the screening grid (Fig. 18). A zero potential has been created in this zone, exactly the same as the protective grid would have if only it existed in this lamp. To create such a zone, constructive changes had to be made. In particular, the anode is further away from the protective grid. The "imaginary electrode" acts on the secondary electrons in the same way as the protective grid, and also prevents the occurrence of the dynatron effect. The electrons in this lamp go from the cathode to the anode as if in separate beams, passing in the spaces between the turns of the grids; hence the name of the lamp - beam. The coils of the grids are arranged so that the shielding grid is in the "electronic shadow" created by the coils of the control grid closest to the cathode. Due to this, the screening grid attracts relatively few electrons to itself, and the emission current is almost completely spent on the anode circuit. On the side narrow sides of the cathode, the lamp has metal shields connected to the cathode, due to which the electrons enter the anode only from certain sides, where a uniform electric field is created. No "electronic swirls" are obtained, which affects the absence of distortion in the operation of the lamp. Beam lamps have a high efficiency and are able to give a very large output power. Suffice it to say that two such lamps in a push-pull circuit, under certain conditions, can deliver up to 60W of useful power.

Lamps are improved not only electrically, but also purely constructively. The first radio tubes in appearance differed little from electric lamps and shone almost the same way. Many people still remember the first radio tubes developed by our compatriots prof. A. A. Chernyshev and prof. M. A. Bonch-Bruevich. In recent years, the appearance of the radio tube has changed a lot. Our domestic scientific thought made a great contribution to the creation of new types of lamps and the improvement of previously produced ones. Suffice it to point to the work of the team of employees of the Stalin Prize laureate, order bearer prof. S. A. Vekshinsky. At first, the radio tube, to the great surprise of novice radio amateurs, stopped shining and was turned only to fulfilling its direct duties. Then the configuration of the balloon was repeatedly changed. There were small-sized lamps a little more than half the size of the little finger. For laboratory-type radio equipment, lamps were produced that were similar in size and shape to acorns. Currently, metal lamps are widespread, which are even somehow inconvenient to call lamps, since they do not glow at all. Replacing a glass cylinder with a metal (steel) one is not an easy replacement: metal lamps compare favorably with glass ones in their small dimensions (a 6X6 lamp, for example, is only the size of a walnut), strength, good electrical shielding (no need to put on bulky screens, like glass lamps ), smaller interelectrode capacitances, etc. True, there are also disadvantages for metal lamps, of which a very significant heating of the metal bulb is very significant, especially for kenotrons.

Now many types of lamps are available in two versions: in metal and glass design. The use of a "key" on the leg of the lamps facilitates the procedure of inserting the lamp into the socket. If earlier it was possible to carelessly touch the sockets of the socket with the wrong pins, as a result of which the lamp, flashing spectacularly for a moment, was permanently out of order due to the filament burnout, now it is impossible to insert the lamp until the pins are in the correct position. Errors leading to the death of the lamp are excluded. Lamp technology is constantly being improved. Its level determines the progress of radio engineering.

U a at the anode. The voltage values ​​on the grid in volts are plotted along the horizontal axis: negative voltages are to the left of zero, positive voltages are to the right. The values ​​of the anode current in milliamps are plotted along the vertical axis, up from zero. Having the characteristics of the lamp in front of you (Fig. 19), you can quickly determine what the anode current is equal to at any voltage on the grid: at U g \u003d 0, for example, i a \u003d i a0 \u003d 8.6 mA. If you are interested in data at other anode voltages, then not one characteristic is drawn, but several: for each value of the anode voltage separately. Characteristics for lower anode voltages will be located to the right, and for large ones - to the left. It turns out a family of characteristics, using which you can determine the parameters of the lamp.

We make the voltage on the grid positive U g \u003d + ZV. What happened to the anode current? It increased to 12 mA (Fig. 20). The positively charged grid attracts the electrons and thereby “pushes” them towards the anode. The greater the positive voltage on the grid, the more it affects the electron flow, which leads to an increase in the anode current. But there comes a moment at which the increase slows down, the characteristic gets a bend (upper bend) and, finally, the anode current completely stops increasing (the horizontal section of the characteristic). This is saturation: all the electrons emitted by the heated cathode are completely taken away from it by the anode and grid. At a given anode voltage and filament voltage, the anode current of the lamp cannot become greater than the saturation current i s.

We make the voltage on the grid negative, move to the area to the left of the vertical axis, to the "left area". The greater the negative voltage and on the grid, the farther to the left, the smaller the anode current becomes. When U g = - 4 in the anode current is reduced to i a =3mA (Fig. 21). This is explained by the fact that a negatively charged grid repels electrons back to the cathode, preventing them from passing to the anode. Please note that at the bottom of the characteristic, a fold is also obtained, as well as at the top. As will be clear from the following, the presence of folds significantly impairs lamp performance. The straighter the characteristic, the better the amplifier tube.

Let's make the negative voltage on the grid so large that the grid repels all the electrons from itself back to the cathode, completely preventing them from passing to the anode. The flow of electrons is interrupted, the anode current becomes equal to zero. The lamp is "locked" (Fig. 22). The voltage on the grid at which the lamp is “turned off” is called the “turn-off voltage” (denoted by U gzap). For the characteristics we have taken U gzap = - 9v. You can “unlock” the lamp by reducing the negative voltage on the grid or by increasing the anode voltage.

By setting a constant voltage on the anode, you can change the anode current i a from zero (i a \u003d 0) to the maximum (i a \u003d i s) by changing the voltage on the grid in the range from U g zap to U g, (Fig. 23). Since the grid is located closer to the cathode than the anode, it is enough to change the grid voltage slightly to significantly change the anode current. In our case, it is enough to change the voltage on the grid by only 14.5V to reduce the anode current from maximum to zero. The influence of the grid voltage on the electron flow is an exceptionally convenient possibility of controlling the magnitude of the electric current, especially if we take into account that this action is carried out instantly, without inertia.

We will uniformly and continuously change the voltage on the grid, making it either positive or negative. To this end, we bring to the grid an alternating voltage U mg1, called the lamp excitation voltage. The graph of this voltage (sinusoid) is plotted on the vertical time axis tgoing down from zero. The anode current will pulsate - periodically increase and decrease with a frequency equal to the frequency of the excitation voltage. The anode current pulsation graph, which repeats the excitation voltage graph in its form, is plotted along the horizontal time axis t to the right of the characteristic. The greater the value of U mg1, the greater the anode current changes (compare U mg1 and I m a1 with U mg 2 and I m a2) (Fig. 24). Point a on the characteristic, corresponding to the average value of the voltage on the grid and the quiescent current in the anode circuit: is called the operating point.

What happens if the resistance R a is included in the anode circuit of the lamp (circuit on the left)? An anode current i a will pass through it, as a result of which a voltage drop will appear on it U Ra, pulsating with the frequency of the excitation voltage. The pulsating voltage, as is known, consists of two terms: a constant (in our case, U Ra) and a variable (U ma). With a correctly chosen value of R a, the variable, the term of the anode voltage U ma in the voltage amplifiers, turns out to be greater than U m g, i.e., the alternating voltage is amplified. The ratio of U ma to U m g is called the circuit gain. If the amplification produced by one lamp is not enough, then the voltage amplified by the first lamp is applied to the second lamp, and from the second to the third, etc. This is how cascade amplification is carried out (Fig. 25). The figure on the right shows highly simplified circuits of three-stage amplifiers: at the top - on the resistances, and at the bottom - on the transformers.

In FIG. 26 shows the same lamp characteristic as in FIG. 24, only without the top and bottom smooth folds. This is an idealized characteristic. Compare Fig. 24 and 26 and you will see what the presence of folds in the real characteristic leads to. They cause distortions in the anode circuit of the shape of the curve of amplified oscillations, and these distortions are unacceptable, especially when they are large. A loudspeaker connected to a distortion amplifier produces hoarse sounds, speech becomes unintelligible, singing becomes unnatural, etc. Such distortion, due to the non-linearity of the tube characteristic, is called non-linear. They will not be at all if the characteristic is strictly linear: here the anode current fluctuation graph exactly repeats the voltage fluctuation graph on the grid.

The characteristics of most amplifying tubes are straight in their midsection. The conclusion suggests itself: do not use the entire characteristic of the lamp along with the bends, but only its rectilinear middle section (Fig. 27). This will save the gain from non-linear distortion. To do this, the voltage on the grid should not exceed -U g 1 towards negative values, and +U g 2 towards positive values. The value of the anode current in this case will vary within narrowed limits: not from i a =0 to i a =i g (Fig. 23), but from i al to 1 a 2 . Within these limits, the lamp characteristic is completely linear, there will be no distortion, but the lamp will not be used to the limits of its capabilities, its coefficient of performance (COP) will be low. In cases where it is necessary to obtain undistorted amplification, this circumstance has to be put up with.

Unfortunately, the matter is not limited to non-linear distortions. At the moments when the grid is positively charged, it attracts electrons to itself, taking away some of them from the total flow directed to the anode. Due to this, a grid current appears in the grid circuit. The anode current decreases by the value of the grid current, and this decrease is all the more pronounced, the greater the positive voltage on the grid. As a result, with positive grid voltage pulses, distortions in the shape of the anode current are again detected. You can get rid of these distortions: in the process of amplification, the voltage on the grid should never be positive, and even better if it does not reach zero at all (Fig. 28). It must always be maintained negative, and then there will be no grid current at all. This requirement leads to an even greater reduction in the length of the used part of the characteristic: to the right of the VG line - grid currents, to the left of the AB line - non-linear distortions. MN - this is the section of the characteristic, using which you can completely get rid of distortion in the lamp; and they are getting smaller as well.

But how to use the MN plot? If only the excitation voltage U mg is applied to the grid, as in Fig. 24 and 26, then the entry into the right area, into the area of ​​grid currents, is inevitable. Let us first bring to the grid a constant negative voltage U g0 of such a value that the operating point a shifts to the left along the characteristic and turns out to be just in the middle of the MN section (Fig. 29). Then we apply the excitation voltage U mg to the grid. Entry into the right region will be eliminated if the value U mg does not exceed U g0 , i.e. if U mg< U g0 . Работая при таких условиях, лампа не будет вносить искажений. Этот режим работы лампы получил название режима А. Батарея, напряжение которой смещает по характеристике рабочую точку, называется батареей смещения, a ее напряжение U g0 - напряжением смешения.

Among other modes of low-frequency amplification, mode A is the most uneconomical: only in some cases the efficiency reaches 30-35%, in general it is maintained at the level of 15-20%. But on the other hand, this mode is the most "clean", the mode with the least distortion. It is used quite often, and mainly in low-power (up to 10-20 W) amplifying cascades, in which the efficiency is not of particular importance. In amplifying tubes with a steeply terminating characteristic, the lower bend is relatively short. Neglecting the introduction of minor non-linear distortions (which, by the way, are completely undetectable when listening to a sound program), one can allow a more economical use of the lamp and include a lower bend in the working section of the MH characteristic (Fig. 30). This mode of the lamp still retains the name mode A.

In textbooks, there is such a definition of the class A amplification mode: this is the mode in which the lamp operates without cutting off the anode current. In FIG. 31 we show what a cutoff is. The excitation voltage U mg is so high that during some part of the period U mg the lamp is completely blocked, the current through the lamp stops. The lower parts of the anode current curve are not reproduced and are, as it were, cut off - hence the name "cut-off". The cutoff can be not only from below, but also from above (upper cutoff, Fig. 28), when the anode current pulse exceeds the lamp saturation current. And so, mode A is a gain mode without cutoff. Guided by this definition, we could assign to this mode the processes graphically represented in Fig. 24 (at U mg2), fig. 26 (the same for U mg2), fig. 29 and 30. But, we repeat, mode A is a mode without distortion: only the process shown in Fig. 1 fully satisfies this condition. 29.

A push-pull amplifier circuit operating in mode A, otherwise called a push-pull circuit (from the English words "push" - push and "pool" - pull), has become widespread. In this circuit, not one, but two identical lamps are used. The excitation voltage is applied so that when one grid is positively charged, the other is negatively charged. Due to this, an increase in the anode current of one lamp is accompanied by a simultaneous decrease in the current of the other lamp. But the current pulses in the anode circuit are added, and the resulting alternating current is obtained in it, equal to twice the current of one vump, i.e. i ma \u003d i ma 1 + i ma 2. This is much easier to imagine if one characteristic is placed upside down under the other: it immediately becomes clear how the voltage U mg (“buildup”) affects the currents in the lamps (Fig. 32). A push-pull circuit operates more economically and with less non-linear distortion than a single-cycle circuit. Most often, this circuit is used in the final (output) stages, amplifiers of medium and high power.

Consider this case: a mixing voltage U g0 = U gzap is applied to the lamp grid. Thus, the operating point is placed at the very bottom of the characteristic. The lamp is locked, its total current at rest is zero. If, under such conditions, an excitation voltage U mg is applied to the lamp, then pulses will appear in the anode circuit, the current I ma in the form of half periods. In other words, the curve of amplified oscillations U mg will be distorted beyond recognition: its entire lower half will be cut off (Fig. 33). This mode may seem completely unsuitable for low-frequency amplification - distortion is too great. But let's wait to draw this conclusion about unsuitability.

We straighten the lower fold at the characteristic (Fig. 33), turning the real characteristic into an idealized, completely straight one (Fig. 34). Nonlinear distortions due to the presence of the lower fold will disappear, but a cut of the half of the curve of amplified oscillations will remain. If this drawback could be eliminated or compensated, this mode could be used for low-frequency amplification. It is beneficial: at the moments of pauses, when the excitation voltage U mg is not applied, the lamp is locked and does not consume electric current from the anode voltage source. But how to eliminate or compensate for cutting half of the curve? Let's take not one lamp, but two and make them work alternately: one - from one half-cycle of the excitation voltage, and the other - from the other, following the first. When one lamp will "unlock", the other at that moment will begin to "unlock", and vice versa. Each lamp individually will produce its own half of the curve, and their joint action will reproduce the entire curve. The distortion will be removed. But how to connect the lamps for this?

Of course, in the push-pull circuit shown in FIG. 32. Only the grid of each of the lamps in this circuit will have to be biased U g 0 = U gzap. While the excitation voltage U mg is not applied, both lamps are "locked", their anode currents are equal to zero. But now the voltage U mg is applied, and the lamps alternately begin to “unlock” and “lock” (Fig. 35), working with impulses, jerks (hence the name of the mode - push-push - “push-push”). This is the difference between the circuit “ push-push" from the "push-pull" circuit (Fig. 32), operating in mode A. In the case of push-pull mode, the lamps work simultaneously, while in the "push" mode they work in turn. If the characteristics of the lamps are perfectly straight, the lamps are exactly the same and the cutoffs for each of them are chosen correctly, then no distortion is obtained at all.This amplification mode, applicable only to push-pull circuits, is called the ideal mode B.

But in real mode B, with real characteristics, non-linear distortions are inevitable due to the lower fold. This forces in many cases to abandon the use of mode B, generally the most economical of all modes of low-frequency amplification. What mode of low-frequency amplification can be recommended? Mode A, as we now know, is not very economical, and its use in powerful amplifiers is not always justified. It is good only for low power cascades. Use cases for mode B are also limited. But there is a mode that occupies an intermediate position between modes A and B - this is mode AB. However, before getting acquainted with it, we point out the accepted subdivision of the existing amplification regimes. If, in the process of amplification, an entry into the area of ​​\u200b\u200bgrid currents, into the right region, is obtained, then index 2 is added to the name of the mode, but if work is performed without grid currents, index 1. This is how modes B 1 and B 2 are distinguished (Fig. 36), modes AB 1 and AB 2. The designations A 1 and A 2 are almost never found: mode A is a mode completely without distortion, and therefore without grid currents. Simple - mode A.

Now let's get acquainted with the AB mode. In this mode, as in mode B, the lamps operate with cutoff of the anode current, but the operating point on the characteristic is to the right and higher than in mode B. At the moments of pauses, the currents through the lamps do not stop, although they are not large (i al and i a 2). The position of the operating point of the RT is determined by the following condition: the resulting ABVG characteristic of lamps operating in a push-pull circuit (AB mode is generally unsuitable for single-cycle circuits) should be as straightforward as possible. At the same time, it is desirable to have small currents i al and i a2, since this largely determines the efficiency. These conditions are satisfied by the position of the operating point of the RT indicated in Fig. 37. The AB 2 mode is more economical than the AB 1 mode (the efficiency in the mode AB 2 reaches 65%, while in AB 1 mode - only 60%); it is used in high power cascades - more than 100W power. In medium power cascades - up to 100W - AB 1 mode is recommended. Distortion in AB 2 mode is noticeably greater than in AB mode 1 .

Finally, another amplification mode is known - mode C. It is characterized by the fact that the operating point in this mode is to the left of the position on the grid voltage axis, at which the lamp is “locked”. A negative mixing voltage U g0 >U gzap is applied to the grid of the lamp. At the moments of pauses, the lamp is "locked", and it is "unlocked" only in order to pass a short-term current pulse lasting less than half the period Umg. Usually, Umg is greater than Ug0 in absolute value, as a result of which an entry into the region of grid currents occurs and even an upper cutoff occurs (as shown in Fig. 38 for U mg2). Distortion in mode C is so great that this mode is unsuitable for low-frequency amplification. But it is the most economical of all modes in general (efficiency up to 75-80%) and therefore is used to amplify high-frequency oscillations in radio transmitting devices, where non-linear distortions are not as important as in low-frequency amplification technology.

How the designations of the lamps are deciphered, how the names of the lamps are formed, what is the difference between multi-grid and multi-electrode lamps, how the electrodes of the receiving lamps are displayed, etc.

How are lamp designations deciphered?

Receiving lamps produced by the Svetlana plant are usually indicated by two letters and a number. The first letter indicates the purpose of the lamp, the second - the type of cathode, and the number - the serial number of the development of the lamp.

The letters are deciphered as follows:

• U - amplifying,
• P - reception,
• T - translational,
• G - generator,
• Zh - low-power generator (old name),
• M - modulatory,
• B - powerful generator (old name)
• K - kenotron,
• B - rectifier,
• C is special.

The type of cathode is indicated by the following letters:

• T - thoriated,
• O - oxidized,
• K - carbonated,
• B - barium.

Thus SO-124 means: special oxide No. 124.

In generator lamps, the figure next to the letter G indicates the useful output power of the lamp, and for low-power lamps (with natural cooling) this power is indicated in watts, and for water-cooled lamps - in kilowatts.

What do the letters “C” and “RL” mean on the cylinders of our radio tubes?

The letter "C" in the circle is the brand of the Leningrad plant "Svetlana", "RL" - the Moscow plant "Radio lamp".

How are lamp names formed?

All modern radio tubes can be divided into two categories: single lamps, having one lamp in their cylinder, and combined lamps, which are a combination of two or more lamps, sometimes having one (common), and sometimes several independent cathodes.

For lamps of the first type, there are two ways of naming. The names compiled according to the first method indicate the number of grids, where the number of grids is indicated by the Greek word, and the grid is indicated by the English word (grid).

Thus, by this method, a five-grid lamp would be called a "pentagrid". According to the second method, the name indicates the number of electrodes, of which one is the cathode, the other is the anode, and all the rest are grids.

A lamp that has only two electrodes (anode and cathode) is called a diode, a three-electrode lamp is called a triode, a four-electrode lamp is called a tetrode, a five-electrode lamp is a pentode, a six-electrode lamp is a hexode, a seven-electrode lamp is a heptode, and an eight-electrode lamp is an octode.

Thus, a lamp with seven electrodes (anode, cathode and five grids) can be called a pentagrid in one way, and a heptode in another.

Combined lamps have names indicating the types of lamps enclosed in one cylinder, for example: diode-pentode, diode-triode, double diode-triode (the latter name indicates that two diode lamps and one triode are enclosed in one cylinder).

What is the difference between multi-grid and multi-electrode lamps?

Recently, in connection with the release of lamps having many electrodes, the following classification of lamps, which has not yet received general recognition, has been proposed.

It is proposed to call multigrid lamps such lamps that have one cathode, one anode and several grids. Multi-electrode lamps are those that have two or more anodes. A multi-electrode lamp will also be called one that has two or more cathodes.

The shielded lamp, pentode, pentagrid, octode are multi-grid, since each of them has one anode and one cathode and, respectively, two, three, five and six grids.

The same lamps as a double diode-triode, a triode-pentode, etc. are considered multi-electrode, since a double diode-triode has three anodes, a triode-pentode has two anodes, etc.

What is a Vari-Slope (“Varimyu”) Lamp?

Lamps with variable slope have the distinctive feature that their characteristic at small displacements near zero has a large slope and the gain increases to a maximum.

As the negative bias increases, the slope and gain of the tube decrease. This property of a lamp with a variable slope allows it to be used in the receiver's high-frequency amplification stage to automatically adjust the reception strength: with weak signals (small offset), the lamp amplifies as much as possible, with strong signals, the gain drops.

The figure on the left shows the characteristic of a 6SK7 variable slope lamp and the characteristic of a conventional 6SJ7 lamp on the right. A distinctive feature of a lamp with variable slope is a long “tail” at the bottom of the characteristic.

Rice. 1. Characteristics of the 6SK7 variable slope lamp and, on the right, the characteristic of the 6SJ7 conventional lamp.

What does DDT and DDP mean?

DDT is an abbreviation for a double triode diode, and DDP is an abbreviation for a double pentode diode.

The conclusions of the electrodes for various lamps are shown in the figure. (The marking of the pins is given as if looking at the base from below).

Rice. 2. How are the electrodes at the receiving lamps.

• 1 - direct filament triode;
• 2 - shielded direct filament lamp;
• 3 - two-anode kenotron;
• 4 - direct filament pentode;
• 5 - triode of indirect heating;
• 6 - shielded lamp with indirect incandescence;
• 7 - direct filament pentagrid;
• 8 - indirect filament pentagrid;
• 9 - double triode of direct heating;
• 10 - double diode-triode of direct heating;
• 11 - double diode-triode of indirect heating;
• 12 - pentode with indirect heating;
• 13 - double diode-pentode with indirect heating;
• 14 - powerful triode;
• 15 - powerful single-anode kenotron.

What is called lamp parameters?

Each vacuum tube has some distinguishing features that characterize its suitability for operation in certain conditions, and the amplification that this tube can provide.

These lamp-specific data are called lamp parameters. The main parameters include: the gain of the lamp, the steepness of the characteristic, internal resistance, quality factor, the value of the interelectrode capacitance.

What is gain factor?

The gain factor (usually denoted by the Greek letter |i) shows how many times stronger, compared to the action of the anode, the action of the control grid on the flow of electrons emitted by the filament.

The All-Union Standard 7768 defines the gain as “a parameter of a vacuum tube expressing the ratio of the change in the anode voltage to the corresponding reverse change in the grid voltage, necessary for the magnitude of the anode current to remain constant.”

What is slope?

The steepness of the characteristic is the ratio of the change in the anode current to the corresponding change in the voltage of the control grid at a constant voltage at the anode.

The slope of the characteristic is usually denoted by the letter S and is expressed in milliamps per volt (mA / V). The slope of the characteristic is one of the most important parameters of the lamp. It can be assumed that the greater the steepness, the better the lamp.

What is the internal resistance of a lamp?

The internal resistance of the lamp is the ratio of the change in the anode voltage to the corresponding change in the anode current at a constant voltage on the grid. The internal resistance is denoted by the letter Shi and is expressed in ohms.

What is the quality factor of a lamp?

The quality factor is the product of the gain and the steepness of the lamp, i.e., the product of i by S. The quality factor is denoted by the letter G. The quality factor characterizes the lamp as a whole.

The higher the quality factor of the lamp, the better the lamp. The quality factor is expressed in milliwatts divided by volts squared (mW/V2).

What is the internal equation of a lamp?

The internal equation of the lamp (it is always equal to 1) is the ratio of the steepness of the characteristic S, multiplied by the internal resistance Ri and divided by the gain q, i.e. S * Ri / c \u003d 1.

Hence: S=c/Ri, c=S*Ri, Ri=c/S.

What is interelectrode capacitance?

The interelectrode capacitance is the electrostatic capacitance that exists between the various electrodes of the lamp, for example, between the anode and cathode, anode and grid, etc.

The capacitance between the anode and the control grid (Cga) is of the greatest importance, since it limits the gain that can be obtained from the lamp. In shielded lamps intended for high frequency amplification, Cga is usually measured in hundredths or thousandths of a micromicrofarad.

What is the input capacitance of the lamp?

The lamp input capacitance (Cgf) is the capacitance between the control grid and the cathode. This capacitance is usually connected to the capacitance of the variable capacitor of the tuning circuit and reduces the overlap of the circuit.

What is the power dissipation at the anode?

During the operation of the lamp, a stream of electrons flies to its anode. Electron impacts on the anode cause the latter to heat up. If you dissipate (release) a lot of power on the anode, the anode may melt, which will lead to the death of the lamp.

The power dissipation at the anode is the limiting power for which the anode of a given lamp is designed. This power is numerically equal to the anode voltage multiplied by the strength of the anode current, and is expressed in watts.

If, for example, an anode current of 20 mA flows through a lamp at an anode voltage of 200 V, then 200 * 0.02 = 4 W are dissipated at the anode.

How to determine the power dissipation at the anode of the lamp?

The maximum power that can be dissipated at the anode is usually indicated in the lamp's passport. Knowing the power dissipation and given a certain anode voltage, it is possible to calculate what maximum current is permissible for a given lamp.

Thus, the power dissipation at the anode of the UO-104 lamp is 10 watts. Therefore, at an anode voltage of 250 V, the anode current of the lamp should not exceed 40 mA, since at this voltage exactly 10 W will be dissipated at the anode.

Why does the anode of the output lamp get hot?

The anode of the output lamp becomes hot because more power is released on it than that for which the lamp is designed. This usually happens when a high voltage is applied to the anode, and the bias set on the control grid is small; in this case, a large anode current flows through the lamp, and as a result, the dissipation power exceeds the allowable one.

To avoid this phenomenon, it is necessary to either reduce the anode voltage or increase the bias on the control grid. In the same way, it is not the anode that can be heated in the lamp, but the grid.

So, for example, screening grids are sometimes heated in shielded lamps and pentodes. This can happen both with too high anode voltage on these lamps and with a small bias on the control grids, and in cases where, due to some error, the anode voltage does not reach the anode of the lamp.

In these cases, a significant part of the lamp current rushes through the grid and heats it up.

Why have lamp anodes been made black lately?

Lamp anodes are blackened for better heat dissipation. A blackened anode can dissipate more power.

How to understand the readings of instruments when testing a purchased radio tube in a store?

The test setups used in radio shops to test purchased tubes are extremely primitive and do not really give a sense of the tube's suitability for operation.

All these installations are most often designed to test three-electrode lamps. Shielded lamps or high-frequency pentodes are tested in the same panels, and therefore the instruments of the test installation show the current of the screening grid, not the anode of the lamp, since a screening grid is connected to the anode pin on the base of such lamps.

Thus, if the lamp has a short circuit between the shielding mesh and the anode, then this fault will not be detected on the test bench in the store and the lamp will be considered good. These devices can only be used to judge that the filament is intact and there is emission.

Can the integrity of its filaments be a sign of the lamp's suitability?

The integrity of the filament can be considered a relatively sure sign of the suitability of the lamp for operation only in relation to lamps with a pure tungsten cathode (such lamps include, for example, the R-5 lamp, which is currently out of production).

For preheated and modern direct-incandescent lamps, the integrity of the filament does not yet indicate that the lamp is suitable for operation, since the lamp may not have emission even with a whole filament.

In addition, the integrity of the filament and even the presence of emission does not yet mean that the lamp is perfectly suitable for operation, because there may be short circuits in the lamp between the anode and the grid, etc.

What is the difference between a complete lamp and an inferior one?

At lamp factories, all lamps are checked and inspected before leaving the factory. Factory standards provide for known tolerances for lamp parameters, and lamps that meet these tolerances, that is, lamps whose parameters do not go beyond these tolerances, are considered to be full-fledged lamps.

A lamp, in which at least one of the parameters goes beyond these tolerances, is considered defective. Defective lamps also include lamps that have an external defect, for example, crooked electrodes, a crooked bulb, cracks, scratches on the base, etc.

Lamps of this kind are labeled “inferior” or “2nd grade” and are put on sale at a reduced price. Usually defective lamps in terms of performance are not much different from full-fledged ones.

When buying defective lamps, it is advisable to choose one that has an obvious external defect, since such a defective lamp almost always has completely normal parameters.

What is a lamp cathode?

The cathode of the lamp is the electrode that, when heated, emits electrons, the flow of which forms the anode current of the lamp.

In direct filament lamps, electrons are emitted directly from the filament. Therefore, in direct-filament lamps, the filament is also the cathode. These lamps include UO-104 lamps, all barium lamps, kenotrons.

Rice. 3. What are direct filament lamps.

In a heated lamp, the filament is not its cathode, but is used only to heat the porcelain cylinder inside which this filament passes to the desired temperature.

A nickel case is put on this cylinder with a special active layer applied to it, which emits electrons when heated. This electron-emitting layer is the cathode of the lamp.

Due to the large thermal inertia of the porcelain cylinder, it does not have time to cool down during changes in the direction of the current, and therefore the background of the alternating current during the operation of the receiver will practically not be noticeable.

Heated lamps are otherwise called indirectly heated or indirectly heated lamps, as well as lamps with an equipotential cathode.

Rice. 4. What is a heated lamp.

Why are lamps made with indirect filament when it would be easier to make lamps with direct filament and thick filament?

If a direct filament lamp is heated with alternating current, then alternating current noise is usually heard. This noise is largely due to the fact that when the direction of the current changes and when the current drops to zero at these moments, the lamp filament cools somewhat and its emission decreases.

It would seem possible to avoid AC noise by making the filament very thick, since the thick filament will not have time to cool much.

However, it is very unprofitable to use lamps with such filaments in practice, since they will consume a very large current for heating. In addition, it should be noted that the background of the alternating current, when the filament is powered, occurs not only due to the periodic cooling of the filament.

The background to a certain extent also depends on the fact that the potential of the filament changes its sign 50 times per minute, and since the grid of the lamp in the circuit is connected to the filament, this change of direction is transmitted to the grid, causing the anode current to ripple, which is heard in the loudspeaker as a background.

Therefore, it is much more profitable to make lamps with indirect heating, since such lamps are free from the listed disadvantages.

What is an equipotential cathode?

An equipotential cathode is a heated cathode. The name “equipotential” is used because the potential is the same along the entire length of the cathode.

In direct-heated cathodes, the potential is not the same: in 4-volt lamps it varies from 0 to 4 V, in 2-volt lamps from 0 to 2 V.

What is an activated cathode lamp?

Vacuum tubes used to have a pure tungsten cathode. Significant emission from these cathodes begins only at very high temperatures (about 2400°).

To create this temperature, a strong current is needed and thus lamps with a tungsten cathode are very uneconomical. It was noticed that when the cathodes are coated with oxides of the so-called alkaline earth metals, the emission from the cathodes begins at a much lower temperature (800-1,200 °) and therefore a much weaker current is needed for the corresponding incandescence of the lamp, i.e., such a lamp becomes more economical in the consumption of batteries or accumulators.

Such cathodes coated with alkaline earth metal oxides are called activated, and the process of such coating is called cathode activation. The most common activator at present is barium.

What is the difference between thoriated, carbonated, oxide and barium lamps?

The difference between these types of lamps lies in the method of processing (activating) the cathodes of the lamps. To increase the emissivity, the cathode is covered with a layer of thorium, oxide, barium.

Lamps with a cathode coated with thorium are called thoriated. Barium-coated lamps are called barium lamps. Oxide lamps are also, in most cases, barium lamps, and the difference in their name is explained only by the way the cathode is activated.

For some (powerful) lamps, in order to firmly fix the thorium layer, the cathode is treated with carbon after activation. Such lamps are called carbonated.

Is it possible to judge by the color of the incandescence of the lamp about the correctness of the lamp mode?

Within certain limits, by the color of the glow, one can judge the correctness of the lamp's incandescence, but this requires a certain amount of experience, since lamps of different types have an unequal cathode glow.

Is it dangerous to heat the lamp base?

The heating of the lamp base during operation does not pose any danger to the lamp and is due to the transfer of heat from the cylinder and the internal parts of the lamp to the base.

Why in some lamps (for example, UO-104) is a mica disc placed inside the bulb against the base?

This mica disc serves to protect the base from the thermal radiation of the lamp electrodes. Without such a “thermal screen”, the lamp base would get too hot. Similar thermal screens are used in all high-power lamps.

Why is it that when you turn some lamps over, you can hear that something rolls inside their base?

Such rolling occurs due to the fact that insulators are put on the conductors that are inside the base and connect the electrodes to the pins when the lamps are pinned - glass tubes that protect the output conductors from shorting to each other.

These tubes in some lamps move along the wire when the lamps are turned over.

Why are the bulbs of modern lamps made stepped?

In lamps of the old type, the electrodes were fixed only on one side, in the place of the lamp where the posts on which the electrodes are fixed are connected to the glass leg.

With this mounting design, due to the elasticity of the holders, the electrodes are easily subjected to vibration. In the cylinders of modern lamps, the electrodes are attached at two points - at the bottom they are attached with holders to the glass leg, and at the top - to the mica plate, which is pressed into the “dome” of the lamp.

Thus, the whole design of the lamp becomes more reliable and rigid, which increases the durability of the lamps when they have to work, for example, in mobiles, etc. Lamps of this design are less prone to microphone effect.

Why are lamp bulbs covered with a silvery or brown coating?

For normal operation of the lamps, the degree of rarefaction of the air inside the cylinder (vacuum) must be very high. The pressure in the lamp is measured in millionths of a millimeter of mercury.

It is extremely difficult to obtain such a vacuum with the most advanced pumps. But even this rarefaction does not yet protect the lamp from further deterioration of the vacuum.

In the metal from which the anode and the grid are made, there may be an absorbed (“occluded”) gas, which, when the lamp is operating and the anode is heated, can then be released and worsen the vacuum.

To combat this phenomenon, when pumping out the lamp, it is introduced into a high-frequency field that heats up the lamp electrodes. Even before that, the so-called “getter” (absorber) is introduced into the cylinder in advance, i.e. substances such as magnesium or barium, which have the ability to absorb gases.

Dispersed under the action of a high-frequency field, these substances absorb gases. The sprayed getter is deposited on the bulb of the lamp and covers it with a coating that is visible from the outside.

If magnesium was used as a getter, then the balloon has a silvery tint, with a barium getter, the plaque turns golden brown.

Why do bulbs glow blue?

Most often, the lamp gives a blue gaseous glow, because gas has appeared in the lamp. In this case, if you turn on the lamp incandescence and apply voltage to its anode, the entire bulb of the lamp is filled with blue light.

Such a lamp is unsuitable for work. Sometimes, when the lamp is operating, the surface of the anode begins to glow. The reason for this phenomenon is the deposition on the anode and grid of the lamp of the active layer during the activation of the cathode.

In this case, only the inner surface of the anode often glows. This phenomenon does not prevent the lamp from working normally and is not a sign of its damage.

How does the presence of gas in the lamp affect the operation of the lamp?

If there is a gas lamp in the cylinder, ionization of this gas occurs during operation. The ionization process is as follows: electrons rushing from the cathode to the anode meet gas molecules on their way, hit them and knock electrons out of them.

The knocked-out electrons, in turn, rush to the anode and increase the anode current, while this increase in the anode current occurs unevenly, in jumps, and worsens the operation of the lamp.

Those gas molecules from which the electrons were knocked out and received as a result of this positive charges (the so-called ions) rush to the negatively charged cathode and hit it.

With significant amounts of gas in the lamp, ion bombardment of the cathode can lead to knocking off the active layer from it, and even to cathode burnout.

Positively charged ions are also deposited on the grid, which has a negative potential, and form the so-called grid ion current, the direction of which is opposite to the usual grid current of the lamp.

This ion current significantly impairs the operation of the cascade, reducing gain and sometimes introducing distortion.

What is thermionic current?

The electrons that are in the mass of a body are constantly in motion. However, the speed of this movement is so low that the electrons cannot overcome the resistance of the surface layer of the material and fly out of it.

If the body is heated, then the speed of the electrons will increase and in the end it can reach such a limit that the electrons will fly out of the body.

Such electrons, the appearance of which is due to the heating of the body, are called thermoelectrons, and the current generated by these electrons is called thermionic current.

What is an emission?

Emission is the emission of electrons by the cathode of the lamp.

When does a lamp lose emission?

Emission loss is observed only in activated cathode lamps. The loss of emission is a consequence of the disappearance of the active layer, which can occur for various reasons, for example, from overheating when a higher than normal filament voltage is applied, as well as in the presence of gas in the cylinder and the resulting ion bombardment of the cathode (see question 125).

What is receiver lamp mode?

The operating mode of the lamp is the complex of all constant voltages that are applied to the lamp, i.e., the filament voltage, the anode voltage, the voltage on the shielding grid, the bias on the control grid, etc.

If all of these voltages correspond to the voltages required for a given lamp, then the lamp is operating in the correct mode.

What does it mean to put the lamp in the desired mode of operation?

This means that all electrodes must be supplied with such voltages that correspond to those indicated in the lamp passport or in the instructions.

If the description of the receiver does not contain special instructions about the lamp mode, then you should be guided by the mode data that are given in the lamp passport.

What does the expression "lamp locked" mean?

By “locking” the lamp is meant the case when such a large negative potential is created on the control grid of the lamp that the anode current stops.

Such blocking can occur when the negative bias on the lamp grid is too large, as well as when there is an open in the lamp grid circuit. In this case, the electrons that have settled on the grid are unable to drain to the cathode and thus “lock” the lamp.

The designation and pinout of the following radio tubes are considered: triode, double triode, beam tetrode, tuning indicator, pentode, heptode, double diode-triode, triode-pentode, triode-heptode, kenotron.

A bit of history

The appearance of transistors in the middle of the 20th century seemed to lead to the complete displacement of the then dominant electron tubes from radio engineering.

One of the main disadvantages of radio tubes was their low efficiency. The heated cathode consumed significant energy and had a short service life. The electron lamp was reproached for the laboriousness of its manufacture, it was necessary to maintain the high-precision geometry of a large number of electrodes in the vacuum tube of the lamp.

The production of electronic equipment on lamps was gradually curtailed. In our country, the number of manufactured equipment based on radio tubes, although it gradually decreased, but the factories for the production of lamps continued to work. Oddly enough, this brought certain benefits to the domestic industry in the early 1990s.

Music lovers played a major role in this. In the end, it turned out that vacuum tube audio frequency amplifiers transmit sound recordings better, more naturally than semiconductor triodes.

Currently the market Hi-Fi equipment filled with sound equipment on electronic lamps, mostly Russian-made.

From all this, we can conclude that the design of radio equipment using vacuum tubes at the threshold of the beginning of the 21st century does not bring regression to radio electronics, but, on the contrary, allows a new, more reasonable look at the field of application of vacuum tubes.

The principle of operation of a radioelectronic lamp is based on the phenomenon of thermionic emission. The process of electron emission from the surface of solid or liquid bodies is called electron emission.

Radio tube device

The device of the radio tube is ingeniously simple. In a glass container there are metal electrodes located in a certain way, one of which is heated by an electric current.

This electrode is called the cathode. The cathode is designed to create thermionic emission. In the bulb of the lamp, under the influence of an electric field, electrons fly to another electrode - the anode.

The electronic flow is controlled by other electrodes located in the lamp, called grids.

Conditional graphic image of radio tubes

The simplest amplifying lamp is triode. Its conditional graphic representation on electronic circuits is represented as a circle. Inside the circle, in its upper part, a vertical line is drawn with a perpendicular segment at the end, which symbolizes the anode, a grid is indicated in the diameter of the circle in the form of strokes, and in the lower part, an arc with taps at the ends is a filament.

The bow above the filament indicates the cathode heater. Lamps with a direct glow of the filament in their conditional graphic image do not have such a bow, for example, a 2K2P battery type, as well as some other types of lamps. In one bulb of a lamp, a triode can be placed in combination with another type of lamp.

These are the so-called combined lamps. On the diagrams, next to the image of the lamp, its letter designation (two Latin letters V and L) is placed with a serial number according to the diagram (for example, VL1) and next to them is the type of lamp used in the design (for example, VL1 6N1P). A conditional graphic representation of electronic tubes of various types with a letter designation is shown in fig. one.

In the figure, letters with numbers indicate: a - anode, C1 - control grid, k - cathode and n - filament. To generate, amplify and convert signals, currently in the designs of radio amateurs, mainly vacuum tubes with an octal base, a finger series and a miniature series with flexible leads are used.

The last two types of lamps do not have a base, the conclusions in them are fused directly into the glass bottle. The cylinders of the listed series of lamps are mainly made of glass, but they are also found in metal (Fig. 2).

Rice. 1. Conditional graphic representation and letter designation of electronic tubes of various types on electronic circuits: a - triode; b, c - double triode; g - beam tetrode; e - setting indicator; e - pentode; g, heptode; h - double diode-triode; and - triode-pentode; k - triode-heptode; l - kenotron; m - double diode with separate cathodes of indirect heating.

Rice. Fig. 2. Variants of constructive manufacturing of electron tubes: a - glass bottle, octal base; b - metal cylinder, octal base; c - glass container with rigid leads (finger series); g - glass container with flexible leads (baseless series).

Electrical parameters of lamps

In modern high-quality audio frequency amplifiers, three-electrode tubes, called triodes, are generally preferred. The general basic electrical parameters of receiving-amplifying lamps, which are usually given in reference books, are the following: gain u, slope S and internal resistance Rj.

Of great importance are the so-called static characteristics of the lamp: anode-grid and anode characteristics, which are presented in the form of a graph.

With these two characteristics, you can graphically determine the three main parameters of the lamps given above. For lamps for various purposes, special, characteristic parameters are added to the listed characteristics.

The lamps used in audio frequency amplifiers are also characterized by such parameters that depend on one or another mode of operation of the output lamp, in particular, the output power and the coefficient of nonlinear distortion.

At high frequency lamps characteristic parameters are:

• input capacity,
• output capacity,
• passage capacity,
• bandwidth ratio
• equivalent resistance of intra-lamp noise.

In this case, the lower the total value of the input and output interelectrode capacitances of the lamp and the greater the steepness of its characteristics, the more gain it gives at higher frequencies.

The ratio of the slope of the characteristic of the lamp to its capacitance serves as an indicator of the stability of the amplification. More gain from a high-frequency lamp can be obtained at high frequencies, in the case when the total value of the input and output capacitances of the lamp is less and the steepness of its characteristic is greater.

When choosing a tube for the first stages of amplification, special attention should be paid to its equivalent resistance to intra-tube noise.

The efficiency of the frequency-converting lamps is estimated by the steepness of the conversion. The slope of the conversion, as a rule, is 3...4 times less than the slope of the lamp characteristic. Its value increases with increasing local oscillator voltage.

For kenotrons, the main parameter is the amplitude of the reverse voltage. The highest values ​​of the reverse voltage amplitude are typical for high-voltage kenotrons.

Kenotrons and diodes

On fig. 3 shows the main parameters, typical mode and pinout of some types of vacuum tubes that are widely used in electronic designs at the present time and used in the past.

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes for wide application.

Kenotrons and diodes

Converter Lamps and Cathode Beam Tuning Indicators

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes for wide application (continued)

triodes

• S is the steepness of the anode-grid characteristic;
• m is the gain;
• Rc - the greatest resistance in the grid circuit;
• Cv - input capacitance of the lamp (grid cathode),
• Sv - the output capacitance of the lamp (cathode-anode),
• Ср - passing capacitance of the lamp (grid-anode);
• Pa is the maximum power dissipated by the anode of the lamp.

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes of wide application (continued).

Double triodes

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes of wide application (continued).

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes of wide application (continued).

Output pentodes

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes of wide application (continued).

Rice. 3. Basic parameters, typical mode and pinouts of some types of electronic tubes of wide application (end).

Literature: V.M. Pestrikov. Encyclopedia of the radio amateur.

The very principle of operation of the lamp is simple - everything is built on the fact that hot objects can throw free electrons into space. However, over 50 years of using lamps, they have become so complicated that discrete transistors are far from them ...

So, if you heat a metal conductor and apply a “minus” to it, then free electrons will fly out of this conductor, it is called a cathode. If you put another conductor nearby and attach a “plus” to it (called the anode), then the electrons will not only fly out of the cathode and form a cloud around it, but also purposefully fly to the anode. An electric current will flow.

The whole problem with building vacuum tubes is that the electrons have to fly from the cathode to the anode in a vacuum. Moreover, in a high vacuum, if gas remains inside the lamp, then it will flare up from the movement of electrons and a gas-discharge lamp will turn out. This, of course, is also a result, but not at all the one we are trying to achieve (although there are also options with gas-filled vacuum tubes).

So, we made a metal flask, pumped out the air from there and inserted two electrodes. At the same time, they thought about how to heat one of them, for this they often make an additional heating wire, such cathodes are called indirectly heated cathodes. They plugged it into the network, the cathode lit up white - the current flowed. So what, why is this thing needed? The whole point is that if you change the poles of the battery, then no current will flow through the lamp - the anode is cold and does not emit electrons.
Congratulations, we got a tube diode.

Diode is definitely a good thing. You can even make a detector receiver.
But it makes little sense.


And the whole point turned out when in 1906 they guessed to introduce a third electrode into the lamp - a grid, placing it between the cathode and the anode.
The fact is that if even a weak "minus" is applied to the grid, then the cloud of electrons that has gathered near the cathode will not fly to the "plus" anode, because inside the lamp there is pure electrostatics, the electrons are pushed by Coulomb's law, and in this form the lamp is "locked ".
But it is worth applying a “plus” to the grid, then the lamp will “open” and the current will flow.
And we, by applying a weak voltage to the grid, can control a fairly strong current that flows between the cathode and anode - we got an active element, triode. The voltage ratio between cathode and anode and cathode and grid is called the gain, in a good triode it can reach close to 100 (no longer theoretical for triodes).

However, that's not all. The fact is that a capacitor is formed between the electrodes of the lamp. After all, both the cathode and the anode and the grid are electrodes separated by a dielectric - vacuum. The capacitance of such a capacitor is very small - about picofarads, but if we have high frequencies (starting from megahertz), then this capacitance spoils everything - the lamp stops working. Moreover, the lamp can be self-excited and turn into a generator.

In this case, the most effective method turned out to be shielding the most harmful capacitance - between the grid and the anode. That is, in addition to three electrodes, one more screening grid must be introduced. A voltage was applied to it, approximately half the anode voltage. Such a lamp with four grids became known as tetrodome. Her gain has increased - up to 500-600.

But this was not all. The fact is that the screening grid additionally accelerates the electrons flying to the anode and they hit the anode with such force that they knock out secondary electrons that reach the screening grid and create a current there. This phenomenon was called the dinatron effect.

Well, how to deal with the dynatron effect? That's right - put another grid!
It must be stuck between the screening grid and the anode and connected to the cathode. This lamp is called pentode.
It was the pentode that became the most popular lamp, it was it that was produced in millions of copies for all kinds of needs.
This is not to say that all the negative aspects of the electron tube were absent from the pentode. But it was an excellent balance between price / reliability / performance. Why was it? He stayed.

Of course, everything did not end with the pentode, there were also hexodes, heptodes and octodes. But they either did not gain distribution (for example, there were almost no hexodes produced in the world), or they were narrow-purpose lamps - for example, for superheterodynes.

Everything that is described here seems to be a bit, but it is 60 years of the development of vacuum tubes, years of “feeling” for parameters.
After all, at first there was generally a poor understanding of what was happening in the lamp. Lamps were gas-filled until 1915, and it is not electrons that move, but ions, which behave a little differently.
In addition, fiddling with materials and shapes of electrodes, the invention of lamp circuitry, and the very principles of lamps were also played with. There were all sorts of traveling wave tubes, klystrons and magnetrons. And what are the lamps with mechanical (!) Control? What about gas-filled lamps, photocells, multipliers, vidicons? Yes, the same kinescope - this is according to the principle of operation of an electron lamp!

Vacuum tubes are a huge field of knowledge, which has accumulated a huge amount of material over 60 years of existence.
Accumulated and died.
Now lamps are used only in very narrow areas - for example, heavy-duty amplifiers or special equipment that can withstand a nuclear explosion. After all, the electromagnetic pulse of a nuclear explosion does not burn tube equipment, as happens with transistor equipment - it’s just that during the explosion, the lamps will fail for a split second and continue to work as if nothing had happened.

And lastly, lamp equipment in production is much simpler than semiconductor equipment, the requirements for accuracy and purity of materials are orders of magnitude lower. But this is the most important thing for a hitman!

91 comments Electronic lamp, principle of operation

I'm afraid it doesn't matter to the stalker. Well, except that he will be brought into the First World War and he will immediately improve the triode to a pentode.

The reason is simple - it is necessary to move science and technology too widely in order to use this knowledge.
All electronic technology is a combination of a very large number of very specific knowledge and skills.
Popadanets, having this knowledge (for example, he is an experienced radio electronics engineer), theoretically can make some kind of unit, but it’s unlikely to teach the locals how to make it.
At best, teach (or rather train a group of performers) to produce a strictly defined model of a simple device. This will not advance science and technology in any way, this device will be an unknown artifact and its components will not be applicable to anything else (from the point of view of the locals). And, as is obvious, the manufacture of such a device of little use will be the result of a huge effort! Need such a hit? No.

The hitman does not need technologies ahead of time, but missed technologies.
Great examples here on the site are the Neusler Bullet and the Field Kitchen. Simple and understandable inventions that appeared centuries after the need arose for them and the technological ability to create them.
Technologies like a thermos are also suitable, not to introduce, but to sell.
Something with small technological refinements can be made, but it will have incomprehensible local know-how. It does not advance science but enriches the hitter.
Radio electronics, due to its complexity, does not fall into any of these categories. It's too complex and abstract to explain, and too high-tech to do it yourself.

• I agree.

  But I would single out a third category - “sealed envelope technologies”. Something that can be left to descendants (well, at best, grandchildren in their old age) to accelerate progress. And here you can write down the device of the atomic bomb.

  • And somehow I am very skeptical about these letters to the future.
    In general, letters without an addressee are a strange phenomenon.

>> Well, except that it will be brought into the first world

And look at the statistics of hitmen. Half of them end up in World War II, thirty percent in the Middle Ages, and another 15 percent - to the father of the Tsar, to save from the revolution. Electronic lamps are more than relevant. 😀

>> but to teach the locals how to produce it is unlikely

Well, actually this site is just to collect data on theories for "teach locals".
That is, to expand the understanding of the hitman.
And the problem here is not that everyone can’t figure this out - but simply because an ordinary person has a very narrow circle of interests and he never got into the rest.

>>Radioelectronics, due to its complexity, does not fall into any of these categories. It's too complex and abstract to explain, and too high-tech to do it yourself.

Complete nonsense from start to finish.
There are no complicated things, there is a lack of understanding.
For example - read how Pythagoras himself described his theorem (not a proof, but only a formulation!) - it all turned out to be very difficult for him there, a feeling of higher mathematics, although for us this is all for the fourth grade (or in which Pythagoras is taught now? ).

Moreover, I can cut you a piece from a translated book on vacuum tubes by Leon Chaffee, 1933.
You read there - just a nightmare, as heaped up, and then you begin to understand that most of it is garbage that seemed important, but is not so, side processes that clog the understanding of the main processes.

If the victim is not able to explain the principle of action, then he himself does not understand it. This is an unshakable rule.
And don't care how complex or abstract the theory is - it all depends on its arrangement in the head of the narrator.

Another question is that they will not believe him without a working sample, but that's how it is.
Well, and a completely third question - is it worth moving it to the masses or creating some kind of “new Rosicrucians” (I am slowly writing the article)?

• Statistics is a good thing 🙂
  but, I repeat, the lamps will be useful to a hitman only in the First World War. Rocking a triode to a pentode is a powerful move.
  In World War II, the pentode was already invented. 1926 to be exact. those. the application gap is about 20-30 years (a triode can be created 10-15 years earlier).
  The problem is that it will not be possible to move the idea to the masses earlier, the development of physics will not allow this. You can make a child prodigy, but progress is not so easy to move.
  Speaking about the abstractness and complexity of radio engineering, I meant that it relies on a huge layer of non-obvious knowledge that was absent before 1900. The idea of ​​an electron and an atom (1911), of electrical resistance (1843) of inductance and capacitance (too lazy to look for, but also the 19th century). All this will have to be opened beforehand, demonstrated to others. Advance science ... With the means of communication of that time, this is a task for many years.

  >>create some "new Rosicrucians"
  But this idea is very reasonable. And efficient. Attract neophytes, demonstrate their power with prodigies, report that only this society knows the Truth (tm) ...
  But keep in mind that this will not be progressorism 🙂 And after the death of the knowledge carrier, everything will go topsy-turvy. By the way, death can happen ahead of time 😉 power is a great bait!

  • >> Speaking about the abstractness and complexity of radio engineering, I meant that it relies on a huge layer of non-obvious knowledge that was absent before 1900

    It doesn't matter what was missing before the hit.
    This can really be developed and the science of that time will raise it all.
    That's just the easiest way to move science - there is inertia of thinking, but it is still less than in industry, because in science you can always find young scientists, but there are no young people among industrialists.

    >> Attract neophytes, demonstrate their power as prodigies, report that only this society knows the Truth

    So I have already written several articles on this topic.
    Here, too, there are pitfalls, but a local breakthrough can be very noticeable.

    >>And after the death of the bearer of knowledge, everything will go topsy-turvy.

    I wrote about it too. The same Mormons and Scientologists managed to survive it. Let's see what will happen to the Moonies.

    • >Radio tubes are useful in any war. And the opportunity to create them will appear somewhere in the region of the war of 1912 (which for a hundred years was called the "Great Patriotic War"), and in general during the Napoleonic Wars.

      1912+100=2012, long before 2012, the Great Patriotic War was called the war of 1941-1945. And which side is Napoleon here?

Well, for electronics, especially for transistors, there is still an interval of several decades when you can get very far ahead of the current state. But this is the end of the 19th beginning of the 20th century. If earlier - unpromising
In earlier periods, it is better to dig towards digital mechanical and hydraulic calculators. Boolean algebra, being a very simple and understandable branch of mathematics, took shape only by the end of the 19th century, although it could have existed in ancient Greece

• It’s more profitable for a popadant to carry transistors than lamps. Lamps are dumb. If the hitman ended up at the end of the 19th and beginning of the 20th century and was going to promote radio electronics (it was useless before), pushing transistors is not much more difficult than lamps (taking into account the total volumes of what will have to be pushed, the difference is insignificant), and the benefit is much greater. This is a quick transition to microcircuits ...

  Iron Felix-type mechanical calculators - a reasonable maximum ...
  Bebidzh's car is a crazy project. It is feasible (theoretically), but due to unreliability (hundreds of thousands or even millions of moving parts), its practical application is almost impossible. Even ENIAC worked with frequent interruptions due to the constant failure of its elements, what to speak of mechanics.

  • 
    However, on the net you can find videos of how people made a triode on their own.
    And there are sad stories when they tried to make a transistor ...

    That is, now - when materials can be bought and devices are available - but go ahead!
    A transistor is an order of magnitude more difficult than a radio tube.

    >> Iron Felix-type mechanical calculators - a reasonable maximum

    This is a concrete dead end. Although we can use it in some narrow niches.

    • • And I knew, I knew that it would come to nuclear reactors! 😀
        In total, there are only two technologies: growing an ultrapure single crystal of silicon and building a reactor with dosed neutron production.
        Elementary! 😀

        • Not with dosed but with constant 🙂 this is a slightly different and much simpler task.
          By the way, it is not necessary to make a reactor, you can make a neutron generator of the type that is used as a neutron detonator for plutonium bombs.

          • There is a complete misunderstanding of the principles and quantitative characteristics.

            In bombs, accuracy in time is needed, a one-time injection of 10E5-10E6 neutrons from a betatron source is quite enough. The main thing is accuracy.

            But 10E6 neutrons on the scale of the Avogadro number (6E23) is nothing.

        • Come on?! 🙂 This is apparently a creative rethinking of the principle of operation of accelerating sources?

          No, it’s possible to break deuterium in principle, only for this you need an energy of the order of a dozen MeV (you can feed the cathode-ray tube with these 10 megavolts - figure it out yourself), but only due to the ratio of the cross section of this reaction to the cross section of banal ionization, the neutron yield will be calculated in pieces per second per kilowatt.

          Yes, there are _similar_ sources with beryllium. But the yield of neutrons there is millions per second (electron energies are about the same, MeV), and beryllium is here precisely because the decay of beryllium is exothermic, you just need to invest a little, and then it will happen on its own. This drastically reduces the requirements for the accelerator.

          The most "productive" are accelerator tritium sources - tritium is accelerated into a deuterium target (up to 10E14 neutrons per pulse with a resource of hundreds of thousands to millions of pulses). That is, just a normal tritium fusion (obviously, it won’t work out like that, but what’s valuable here is that it’s not spent so quickly and not so much).
          Voltages are required there - tens-hundreds of kV, which is already more acceptable (you only need to initiate a reaction, and not break off a neutron, keV per nucleus, not MeV).

          If without tritium, then in order of neutron output: deuterium with combined magnetic-inertial confinement (fusor with coils) - up to 10Е11 neutrons per pulse, inertial-static (classical fusor) - up to 10Е9, deuterium with a cold target - up to 10Е10, but consumption higher energy, of course.

          All this is absolute high-tech, all figures are the achievements of modern science and technology (in particular, the power supply unit there is the cutting edge of electronics).

          The simplest and most accessible intense source is some kind of active alpha isotope such as radium-226 mixed with beryllium (metal or oxide). California or polonium laboratory sources produce up to a million neutrons per second.
          Radium will give less, but this is the ONLY real way to get at least a thread of a significant number of neutrons.

          Now remember Avogadro's number: every 28 grams of silicon contains 600,000,000,000,000,000,000,000 atoms. For every few hundreds to thousands of silicon atoms, an impurity atom must be provided.

          Nuclear alloying without INDUSTRIAL, multi-megawatt nuclear reactors (and with a noticeable reactivity margin) is not even nonsense, this is illiterate nonsense, forgive me.

          • Yes, it doesn't seem to work without a nuclear reactor.

            With an amount of phosphorus of 10 ^ 13 per cm3, its conductivity is only just equal to the intrinsic conductivity of silicon. In fact, it is necessary, apparently, of the order of 10 ^ 17, from somewhere I got an estimate of the order of millions, I remembered about the relatively low productivity of the sources and the Avogadro number. But for the beginning of the 20th century, it will do with the reactor.

            • Not every reactor is suitable here. For example, the density of the neutron flux in the RBMK (in which in Russia they just wanted to do nuclear alloying) is about 4E13 neutrons / cm2 * s
              It is clear that only a few percent can be taken from there, otherwise the reactor will stop.

              If we take 10E17 as the target, then it turns out that it takes 10E5-10E6 seconds to achieve concentration - days-weeks.

              And this is one of the most powerful / cheap sources of neutrons available to people today. Kandu - the reactivity margin is less, and hulled ones of all types are fundamentally unsuitable because of the need to stop the reactor to change the target ...
              There are research / medical ones, but there neutrons are already much more expensive ...

              >But for the beginning of the 20th century, it will do with the reactor.

              But nothing that it was first created in 1946? That is, in the middle of the century, and not at the beginning.

        >Neutron generator is heavy water which is directed by a powerful electron tube.

        Water is enriched to heavy by electrolysis, electron tubes were used at the end of the 19th century (X-ray).

        Isotopic enrichment by electrolysis? Seriously?

      What you described is some kind of exotic, perhaps for heavy-duty devices. Microcircuits are doped by the banal method of ion processing in vacuum. But, as I already wrote, everything is much simpler with germanium - two tablets of indium sneak onto a pre-doped crystal and all this is heated until it melts. Germanium devices were industrially manufactured in due time in this way.

      Nuclear doping is still exotic (especially since it fundamentally introduces only one type of impurity: phosphorus). Usually all the same banal diffusion and ion implantation.

    This is not a dead end at all, just the understanding of the principles of operation really came when the styles were available to electromechanical relays and lamps. In their absence, mechanical calculators make it possible to solve a number of problems that are very important in practical terms. For example, automatic target tracking in ship gun mounts. Courses and speeds of own ship and target are entered, after which the computer independently controls the rotary and tilting mechanisms of the tower.
    So maximalism is inappropriate here

    • Oops, I forgot about this kind of tasks 🙂
      Indeed, in the field of simple automation, mechanics completely steers ...

      Naval mechanical ballistic computer provides a HUGE advantage

      • Not only a ballistic computer - a lot of tasks. It's just that now they are solved by cheap microcontrollers and no one even thinks about it. The same management of complex machines from this area, for example. Or a classic of the genre - the control of a weaving machine.

    >>> Transistors, of course, are much better than lamps.

    Not always, in conditions of high radiation or high temperatures, transistors simply do not work, and lamps feel quite tolerable ... Modern lamps naturally ...

    Well, rectification of high currents is still the undivided patrimony of electronic tubes ...

    And miniaturization for lamps is also not a problem - planar lamps can be made almost so small that they do not need a vacuum ... 🙂

    • How did your answer translate "transistors are not always better" into "better without transistors"?
      It is clear that there are narrow niches - well, in such niches, in some places, steam locomotives also thrive.

      • That's something I didn’t notice that I had written “better without transistors” ...

        Nevertheless, lamps can be made even in the Middle Ages, with a mass of gimor, of course, but you can, but alas, transistors can’t ...

        \\It is clear that there are narrow niches - well, in such niches, in some places, steam locomotives also thrive.\\
        Low-frequency amps on llamas have been and will be better than transistor ones. The lamp does not cut the edges of the sinusoid - the sound is velvety.

  That's just with the reliability of the mechanics, everything is fine. Take an interest in the ship's mechanical calculators - amazing designs.

  >>>Lamps are a dead end.

  Who told you this?

  Another question is that few people know about it ...

  Lamps are by no means a dead end, you just don’t know that the development of lamps did not end with the advent of transistors ... 🙂

  And there's a lot of new stuff out there...

  For example, incandescent lamps ...

  And lamps without a vacuum ... 🙂

  And microcircuits on lamps ... 🙂

  If interested - google

  • >And microcircuits on lamps...

    If interested - google

    • >>> Despite the fact that they still cannot produce more than two lamps with similar characteristics. The characteristics of transistors were stable even in the last century. So where are the accuracy requirements? In the case of one simple amplifier, the stability of the characteristics is not critical, it can be adjusted. And then yes, the lamp is simpler. And the accuracy requirement is lower for the lamp. And in complex devices, it is critical, up to the working condition. And here, even modern industry does not "pull".

      Here we are talking about other lamps, and the purpose is different ...

      For digital technology, the accuracy of analog parameters is not particularly important, but if we consider that lamps are made in a technology similar to that of transistors, then the spread of parameters is approximately the same ...

      If you're interested, it's in this book:

      This book, although devoted to such a special area of ​​technology as electronic vacuum tubes, is nevertheless popular science. The classification of electronic devices, their history and evolution, the place of electronic vacuum tubes among other devices, their role in the development of civilization, attempts to hybridize vacuum and semiconductor or vacuum and gas-discharge devices are considered in an accessible and fascinating form. It is told about the principles of operation, design and technology of grid lamps, klystrons, traveling wave lamps, magnetrons and M-type devices in general, about the gyrotron, orotron, vircator, problems of increasing power, frequency and efficiency. The problems of electron sources for devices - thermionic, secondary electron and other cathodes, as well as anti-emitters, the principles of design and operation of composite materials are considered separately and in more detail. The book is addressed to a wide range of readers interested in technology and its history. Engineers specializing in the field of electronics, teachers and students of technical universities will find a lot of useful information in it.

> Boolean algebra, being a very simple and understandable branch of mathematics, took shape only by the end of the 19th century, although it could have existed in ancient Greece

With manual logical calculations, it's just easier not to try to mathematize them. Boolean algebra could have been created even in ancient Egypt, but it can only really be spread if there are devices for automatic calculations. Still not manually controlled adding machines, namely automatic computing devices. Moreover, before binary processors, even three-valued logic has more chances, since not all quantities are always known.

And what are the requirements for the metal of the electrodes? As far as I remember, different metals emit electrons differently.

And someone promised to consider ceramic and metal housings for vacuum tubes. So as not to bother with soldering the electrodes into the glass. 🙂

• The electrodes are ordinary, except for the cathode, which ejects electrons.
  The issue here is the emission temperature. At first, you can just use tungsten, but it emits at a temperature of over 2 thousand degrees.
  Well, then - salts of rare earth elements, I will still describe.

  Well, about the cases - yes, at first you can use cermets (with pure ceramics, there will be no less fuss, if at all possible).
  But glass cases have many advantages, and besides, they are much more technologically advanced. There are no problems with soldering the electrodes, just the electrodes need to be made from
  This is a topic again and I will write again.

  • They also shoved thorium into it, which, due to radioactivity, gave an electron cloud. I wonder if something evil is stuffed into the cathode, is it possible to start a lamp without heating the cathode? The advantages are significant - in the era of lamp technology, I would certainly very much like this, but if they didn’t, it means an insurmountable problem. Who knows where and how?

    • Pure beta emitters (nickel-59 for sure, I heard about strontium-90, but did not see it) were used in some places for this purpose.
      The “advantages” there are dubious: there is already a very large energy of electrons, there is not a “cloud”, there are “sprays” flying with VERY high energy constantly in all directions, which gives a “zero current” and serious noise. This cannot be cured even by reverse bias: the electron energies are very high.
      It makes sense in some places (some gas-discharge devices, ion lamps, special lamps for stochastic amplifiers), but in general - no, byaka.

      There is another technology. And very popadanskaya in fact.

      Lamps without cathode heating are made (in the sense, and are now being made, for the military) on auto emission, and this (with thermally expanded graphite). It’s quite a hitman technique, it’s technologically easier to intercalate graphite (even purity is not critical) than to sculpt a heated cesium or barium electrode.
      But there are some troubles: a high voltage is required (from kilovolts), a relatively low density of the emission current.
      The amplifying triode will have a too nonlinear CVC in the initial section, for a magnetron, the really achievable currents are not enough.

      Circuitry will need to be built a little differently.
      The technology has its own very convenient niches: the classic CRT, the kinescope with this technology win significantly. The start is instant, the consumption is less, the resource is higher.
      If we consider getting somewhere like the USSR of the 40s and 50s, then lamp circuitry and radio engineering would generally develop differently. For example, field emission lamps are a very real energy-saving alternative to mercury ones, and at a price comparable to incandescent lamps. The technology could have started in the same 50s, when electricity was very expensive, and there would simply be no niche for mercury to appear.
      The technologies are comparable in efficiency, but cathode lamps (the lamps themselves) are simpler, cheaper, less dependent on temperature and turn on instantly.

      In addition, the development of the principle could lead to tube microassemblies comparable to the first hybrid PP-circuits, the competition with semiconductors would be much fiercer.

      In general, this technology could play out much wider than in the real world, if it had started at least 20 years earlier - until the problem of the blue LED was solved. It's probably too late now.

      • Quite curious. Intercalation with the same cesium or what is simpler? The same potassium / barium?
        Wouldn't a lamp transformer be a little expensive, given only 50Hz? Will it not blink?

        Especially in a CRT, will the current be stable with such a cathode? Why are they not currently used in the same electron microscopes, and generally they are usually heated?

        Z.Y. It’s a pity for the DRLs - how many of them were messed up on their knees ... 🙂

        • There is no cesium, intercalation is only needed to “fluff” graphite into graphene sheets (sulfuric acid is a common method of thermal expansion).
          Graphene sheets form a kind of "atomic needles", with _very_ high field strengths at the ends at an acceptable voltage. Alternative electrodes for field emission have long been tried to grow from silicon nanowires, from cesium, from tin oxide, and even to install bundles of nanotubes. Some are acceptable, but no alternative comes close in performance and stability to graphite/graphene.
          And technologically there is simply an abyss: gold and cesium are CWD, silicon nanowires are already lithography + etching.

          Transformer - yes, a little expensive. But the DRL also requires iron and copper in the control gear + garbage in the form of a starter.
          It will blink exactly as much as the phosphor will allow. And between us girls, it is much easier to make an inertial phosphor than a “blinking” (that is, fast) one: the first cathodoluminophores were just that. Remember oscilloscopes for slow processes, where the beam ran for almost half a second across the screen, and its path was remembered for a long time by illuminating phosphor? It's not a problem at all. Moreover, it can be smoothed with a capacitor. CRT is a diode.

          This is a relatively recent technology - this nanotech (without quotes) simply never occurred to anyone before. Yes, they tried to make sharp cathodes, but what is “sharp” compared to the atomic plane? Even graphene and nanotubes have not at all exorbitant emission characteristics, even at high voltage.
          And the electrode must also have a resource, the current density there at the tip is wild, a little overdone - and explosive emission. That is, what is needed is a forest of atomically sharp electrodes, easy to manufacture, wildly conductive (yes, that’s why graphene rules) ... Until a certain moment, it never occurred to anyone HOW to do this AT ALL ?!
          It was not in vain that people in the 90s poked silicon nanowires for this purpose (then field emission screens were considered as a “flat” replacement for CRTs). They did not know about nanotubes, they did not know about graphene, they did not know how to calculate the anisotropic work function at all (I'm not saying that they are good at it now :)).

          Therefore, this is a truly popadan technology: behind the seeming simplicity there are knowledge and thoughts that were obtained at another, higher technological turn.

          It is not used now corny because of inertia. Well, the current density from heated cathodes is higher, the linearity of characteristics, a proven, predictable technology, compatibility with low voltages ... autocathodes also have inconveniences.
          But the main reason: after all, cathode-ray devices are now too small-scale to conduct R&D to improve their secondary characteristics. Where there is a lot of money and characteristics are important (warriors + TWT, let's say), it is being introduced (elk).
          But there is less and less room for lamps even in warriors and even in microwaves.

          • There are doubts about a slow phosphor with a good quantum yield. And they are saturated accordingly, about 4 times lighter ...
            Otherwise, all gas-discharge lamps would be made on them, and they would not break their eyes at 50 Hz blinking.

            As for the capacitor, I'm not sure ... The graphene coat certainly lives its own life, and at the same potential, the current will dance. However, for a light bulb it may not be significant.

            But a transformer for kilovolts and 50 Hz is not only expensive, but also cumbersome. Those. or some kind of impulse to make, or something else ... And with the element base - bad!

            Those. The technology is interesting, but questions remain.

            • There is no doubt: I had a diploma in reserve. Cathodic issues were also touched upon. 🙂
              To saturate? Me ... even in a classic kinescope, where the spot area under the beam is less than tenths of a square millimeter and the power is tens of watts (estimate the power density :)), it’s still sawing and sawing. Yes, degradation is notable at the same time, yes, the efficiency drops (due to heating), but in order to reach saturation, you need to work very hard.
              The most classic zinc sulfide, known almost from the first days of cathode rays, is still one of the champions in quantum yield. And yes, it's usually very slow (it can get relatively fast, but that requires extreme technology - it's about the oxygen). Yes, there are nuances (there are a lot of radiating centers, there are also many different traps), but if you don’t dig deep, purely practically, everything is OK.

              Gas-discharge is, generally speaking, something else. That is, there is a certain similarity and intersection, but UV excitation has its own specifics, fast electrons have their own. And I don’t know what kind of lamps you use, for a long time no one breaks eyes at 100 Hz blinking. As soon as it became at least somehow important for consumers, they added inertia and straightened out the spectrum. You can’t get rid of it completely, there is an exponent in most processes, and no matter how you turn it, at the very beginning it is very cool, nothing can be done about it.

              There is not such an intense intimate life in that graphene. The capacitor helps.

              Transformer - yes, expensive, yes, cumbersome. You can breed high volts, which is also not very tempting.
              But all light sources have their own troubles (ha! As if it was just with DRL or HPS!). By the way, the guys who are now in Russia trying to promote this technology to the market as an alternative to mercury energy-saving devices have buried themselves in the pulser (rather cheap), by the way. There is such a group, I know people.

              There are questions, not without that, yes. Moreover, now there are a lot of alternatives.
              But what technology without questions? And even if the technology is not comprehensive, there are niches and times where it sits down tightly, like a glove.

              • \\ By the way, the guys who are now in Russia trying to promote this technology to the market as an alternative to mercury energy-saving devices have buried themselves in the pulser (rather cheap), by the way. \\

                It's cheap NOW. And in the 50s...

                \\ As soon as it became at least somehow important for consumers, they added inertia and straightened out the spectrum. You can’t get rid of it completely, there is an exponent in most processes, but no matter how you turn it, at the very beginning it is very cool, nothing can be done about it.\\

                Can be straightened. But - yes, the exhibitor, and it's good to extinguish it - relaxation in seconds is needed. Nobody could add such inertia.

                By saturation - the same song. If instead of microseconds - seconds, then you already need to count. Maybe for electrons this is not important, but in fluorescence the plug is permanent.

                And another point: electrons, they will give X-rays and bitches, albeit soft. Those. you can’t put a thin glass ...

                • In the 50s - only centralized power supply with high current. But I don’t see any trouble here: we have 30 kV in the AC network on the railway, and nothing, somehow lives. Why not stretch high in the lighting network to city lighting? Yes, isolation is more expensive. But the wires are thin. 🙂

                  It is just impossible to straighten the pitalovo in mercury: there will be asymmetric wear of the electrodes. You can increase the frequency, as in modern ballasts (although, is it already a ballast? Even the brightness is smoothly regulated there, and the ignition can be high).

                  It’s interesting with X-ray: there are two components - characteristic (everything is simple here - don’t shove materials with a hard K-line under the beam, and everything will be OK) and normal inhibitory (here, NNP, something like the fourth degree of effective Z materials). That is, if under the beam there is aluminum (1.5 keVa characteristic) and alumina grenades (aluminum and oxygen, effective Z is somewhere near the plinth), then X-rays will not pass through a thin glass. Is it possible to hammer MeVami, but this is inconvenient for another reason. 🙂
                  The glass can also be lead (for street lighting it is more profitable to take high voltages), this is not such a problem. In the end, hard UV from DRL is also a misfortune, and a double bulb is not a hindrance to use.

                  That is, these problems are rather speculative even for you and me.
                  In the USSR of the 50s, where a gamma relay could be installed as a bunker load sensor or to switch the tram switch (yeah, that's so tough, no one said that we live in a fairy tale), the question would not even be raised.

                  Kilovolts on lanterns? Oh, what an interesting life will come, especially among teenagers :). But, natural selection is good! 🙂

                  It is possible (and necessary) to straighten the pitalovo. One coil burned out - turned the lamp over, it continues to work. The resource is almost twice as high!

                  X-ray - for powerful street lamps with a heavy and expensive bulb - yes, it's normal and imperceptible. For rooms, analogues of 40-60W incandescent - no need. Not under it the technology is ground.

                  Gamma relay, etc... Well, they also do urinotherapy, but that doesn't mean that it should be done this way :).

              And one more thing - to bring such cathodes - for any SEM is needed. In the 50s, it's stressful.

              By the way, one of the quite hit-and-miss technologies is AFM. There will be no practical use, but the Nobel Prize somewhere in the 60s is easy.

              • No. 🙂 SEM is needed not in any way, but in a good way. 🙂
                In principle, after specifying the approximate region of the optimum, the systematically applied poking method gives excellent results.

                The approach was different, more practical. 3 unknown how influencing parameter? Ten variations for each on a logarithmic scale, a thousand samples ... We do, measure, look at trends and areas suspicious of the optimum. A thousand more samples - we specify. This is not even R&D, but this is a topic for a graduate student.

                IMHO, hitting for periods of less than 50 years is no longer quite hitting and progressorism. 🙂
                Here, the shorter the casting time, the closer to “so that I was as smart yesterday as my mother-in-law tomorrow” ...

                Well, basically everything is like that. Having a dozen articles in your smartphone, you can do it without SEM...

                And about “50 years” - this is usually not discussed here until BB2 :). Partly also because the closer - the easier it is to demonstrate ignorance of the subject;).

                I think even though terms of less than 50 years are not discussed for another reason 🙂
                There is not so much ignorance as the absence of truly global ideas ahead of time that one erudite person can implement. It takes a lot of work, preferably a powerful team.
                For example, the same transistors or microcircuits: it is enough to state the general principles to the same Losev or Yofe and the matter will spin, but without you.
                It is possible to recall that gallium arsenide is used in LEDs, but it is not a fact that this will immediately give a result, an experimental search will be required, so the Nobel Prize will be awarded to those who, based on this hint, will bungle super-bright LEDs.
                But the exact recipes are painfully specific, you can’t get them from the literature, only if you yourself have been doing this for a long time in practice. Here the question is what is our special hitman. A senior researcher from a semiconductor laboratory can greatly advance radio engineering in the USSR in the 30s-50s, a specialist in polymer synthesis will make similar breakthroughs in chemistry, but in each other's fields they can hardly help at all.
                In the last 50 years, science has become much less global and the price of a narrow specialist has risen. At this time, a hitman can throw in a few specific technical solutions with which he is familiar, can push science to a common beneficial direction - electronics-computers and genetics-GMO-biotechnologies, but nothing more.
                And specific recipes, they have a painfully narrow range of applications.
                For example, there are several specific improvements that the T-34 tank can be subjected to in 40-42. Previously, this tank did not exist, later they themselves came up with. Improvements significantly improve the quality of the tank and reduce the complexity of its manufacture.
                But as already mentioned, they are only suitable for 40-42 years. Well, what's the point of discussing them?

                And by the way, yes, the example with diodes is excellent. They knew from the very beginning that gallium arsenide steers, they could also make it glow for indicator purposes almost immediately. But super-bright BLUE diodes - this is such a story about which you can write a whole epic. Or make a Hollywood movie when a genius works, works, works, experiencing difficulties, everyone does not believe him, his wife leaves, he already despairs, but comprehends the Eastern Wisdom and works, works, works again.
                And in the end - an absolute victory: a blue diode (a hairdressing competition was won, a deal was made, first place at the Olympiad, etc.).

                To repeat this 20 years earlier, you still need to be Nakamura or something like that.

                // To repeat this 20 years earlier, you still need to be Nakamura or something like that.
                Well, or exactly know the secret and be able to repeat it in the laboratory by virtue of their profession.

                By the way, there is one more thing: a glider, a steam engine, a balloon - they can be built by one person. Of course, with the availability of materials and local workers who can be entrusted with cutting out the necessary details.
                But during the Second World War, one person will NOT be able to do the Su-27 or T-90. Even with any helpers! And the T-72 will not do it. And even the T-55. He will have to limit himself to improvements to the T-34 or, in extreme cases, with a very good knowledge of the history of tank building, stir up the development of the T-44.
                Again, neither the "Competition" nor the "Metis" can be mastered by one person, and even the RPG-7 cannot be repeated, you will have to limit yourself to organizing the development of a mixture of RPG-2 and RPG-7, what will happen here.
                Note that here we are talking about the organization of development and not about direct production. Even PPS-43 cannot be made. Rather, one copy can and will be stirred up, but the secret of PPS-43 is not in combat, but in technological characteristics, you need to know HOW it is cheap and fast to produce and not how it works.

                Delete the steam engine from the list, you cannot build it alone.

                It's not "or". Here it’s just not a matter of knowing a certain “secret” (well, like with LEDs - use a solid solution of gallium nitride). It is necessary to know exactly the whole set of technologies - the cultivation of heterostructures, for example, Alferov received his Nobel Prize for it not in vain, this is not an idea, this is a technology.

                That is, yes, a person must work precisely in this very area, and precisely on this very subject. General erudition and even a course in semiconductor physics is not enough.

              \\Now in Russia they are trying to promote this technology to the market as an alternative to mercury energy-savings\\ Offtopic, but they are engaged in masturbation. With current LEDs...

              • They started about five years ago, the layout was different ... They settled in a typical "valley of death" for startups.

                There was a reason, and there is still some.
                - cathode lamps are more economical than energy-saving ones and are somewhere at the level of "long" lamps.
                — cathode lamps are cheap, and they can be produced in the same production as incandescent lamps. Not without interference in the process 🙂, but the alternative is the complete closure of factories. They are really cheap. Without BP - at the level of LN.
                There is no mercury in cathode lamps. This is actually a very strong argument, if not for consumers, then for people in responsible positions in the state. In reality, all mercury lamps do not go to collection points, but simply to a landfill, and mercury scattered near habitats is not what people really need.

                LEDs are very good now, but in mass high-power lamps they are just getting closer to 100Lm / W, that is, only now they _began_ to overtake “long” mercury tubes, for which 80-90Lm / W is already the norm. At an incomparable price per lumen.
                Cathode lamps are actually mercury killers. Not LEDs - those are too good. And too expensive. 🙂

                Even 5 years ago it was clear that mercury ones were becoming obsolete. Now even more so. Prices for LEDs are already comparable, and will fall to absolute pennies.

                As for environmental friendliness - X-ray. It doesn't matter how bad it really is - the very fact of its presence will not allow you to get "green" buns.
                In general, the prospects are zero from the very beginning, except that they can eat money for startups, while they gave ...

        In principle, carbon cathodes can also (and probably should) be slightly heated. Let's get higher emission density, linearity and all sorts of other charms of conventional thermionic electrodes.

        Carbon is still better than cesium. Despite the low cost, the work function of regular carbon cathodes is comparable to the best cesium cathodes with a longer resource, stability of characteristics, and even current density.
        That is, at the same temperature, such carbon is better. Cesium / barium is not needed in most cases (only for solar cells, dynatrons and the like), IMHO, this is a way around the ideal, a whim of the technical history of Mankind, which would not have to be repeated.

        • However, no. Graphite will certainly not withstand both heating and high currents ...

          • An article about graphite should be written separately. There were adventures with mining, when the mine was opened for several months every seven years (I don’t remember the exact numbers, I have to dig up).

            And graphite is not for electrodes of electronic lamps (I don’t believe in it), but for electrodes of electrolyzers (the same aluminum from the melt), for muffle furnaces, for generator brushes. Well, everyday life is different, our pencil is everything.

            Well, about graphene - generally pure fantasy, IMHO.

            • What does "do not believe" mean? 🙂
              And do you believe in tungsten and cesium? To become, canonically, without apocrypha and entih new non-Christs? 🙂

              It's physics and technology. Okay b, it was abstract theoretical physics, but this is a real-life technique. Fantastic, not fantastic… it works.
              Sobssno, no one has anything to do with sheets of pure graphene, if you look under an electron microscope, it all looks very untidy. But the end result suits everyone, and this is the main thing, right?

              Do you think that now technical graphite is mined in mines, or what? 🙂 No. Where controlled properties are needed, it is pyrolytic.

              • Give me a link with the details of how it works there.
                If it is really sane from the point of view of antiquity, I will collect an article.

                And then yesterday I wrote about barium magnets, there were statements here that it was not difficult ...

                And also - references to the technology of pyrolysis graphite ported in antiquity - are welcome.

                These circuits are just a demonstration of the characteristics of the lamp and nothing more ... for the operation of a lamp oscillator, even the simplest one, you need to complicate the circuit ... for example, add an oscillatory circuit and feedback so that the generator does not self-excite ... you will need accurate stabilization of the operating point in the RF circuit ... hardly realizable ...

                We need a practical circuit that works ... look at the magazines at the link above, there are many circuits of the simplest lamp devices that will actually work ...
                Separate attention to the manufacture of the detector, and detector pairs ...

                Here's about the spark transmitter: http://sergeyhry.narod.ru/rv/rv1926_03_08.htm, it's really possible to make one yourself with copper and iron .... battery copper, zinc, copper sulfate or salt. or your post or bank...

                “Radio Vsem”, No. 7, April 1928 Article All about regenerators Otherwise, the grid rods were shifted by half a millimeter in one direction and the anode rod in the other, and the current-voltage characteristic of the device became, well, completely unique, but it doesn’t look like one other lamp.

                • 1) Standard insulators can help with installation accuracy - plates at the top and bottom. It can be stamped from hot glass or some kind of ceramic. A steel stamp is enough for a couple of hundred, then we'll cut out another one.
                  2) CVC will float from lamp to lamp anyway, so you can’t get away from trimmers.

                  The very design of the rod lamps contains 3 plates of mica punched on the machine plus guide caps pressed into this mica (brass by the way) the rods of the grids themselves are symmetrical and preformed, like the plates of the first grids and the anode (there are petals for bending or welding) - so nothing you can’t move it - the design of the anodes does not allow, but only manual assembly under a microscope (the most difficult installation and tension of the filament).

            I propose to open a separate discussion on the topic of lighting in the history of the world and the possibilities of a hitman in improving it!

            Greetings! I saw a video on youtube with devices without a flask, I don’t know the exact details, but it seems to work. Even the amplifier and generator are shown.
            The cathode of such a lamp, whether it is a triode or a diode, is heated by a burner. I myself tried to make a diode, conductivity was observed, I did not check further.
            So far I am successfully mastering industrial lamps, but I really want to make my own, for the experiment.
            Something remotely resembles one generator, where the flame was placed between the electrodes and subjected to a strong constant magnetic field, an electric current arose. I just don't remember the names.
            Well done site creators, very interesting resource!

            It would be nice to talk about gas-filled lamps (thyratrons, for example), which do not require a vacuum. With analog signals, they are not very good, but, for example, a multivibrator generator or a rectifier for alternating current can be easily made. Well, and rather sophisticated digital-analog devices, such as logic elements (control and monitoring systems, adders are different there for simple calculations), time relays, and so on.

            • A small amount of halogen gases can be easily isolated in successful chemical production. And mercury vapor, even in powerful thyratrons, is used for atomic bombs. 🙂

            >>>> Lamps are a dead end.

            Who told you this?

            They are still used and, moreover, are being developed, and not so long ago they crossed the 100-nanometer mark...

            Microlamps? And this is not a perversion?

            >It will be the easiest thing to move science - there is inertia of thinking, but it is still less than in industry, because in science you can always find young scientists, but there are no young people among industrialists.

            And I took the example of the one who created his own state. And you can inherit the plant at three, and even in infancy.

            > rectifying contact. By combining, you can ALWAYS rivet diodes, field-effect transistors, thyristors and the first primitive microcircuits. Almost on my knees, yeah ... Strongly difficult?

            What's serious? Nuclear reactor on the knee? Isn't it easier to create problems for yourself and others?

            In this article, Nyle Steiner describes experiments on the electrical conductivity of a spirit lamp flame. http://www.sparkbangbuzz.com/flame-amp/flameamp.htm
            He managed to build an operating "flaming" (similar to a vacuum) triode. And also using a double "fiery" to assemble a multivibrator.

            • Funny ... quite a hit-and-miss approach))