Handbook of generator lamps. Generator lamps
In 1913 German. scientist A. Meisner first used a triode to generate oscillations high frequency. In the first years of Soviet power, the most significant developments of G. l. were carried out under the leadership of the Soviet scientist M.A. Bonch-Bruevich in the Nizhny Novgorod laboratory (Gorky). In 1919, he was the first to use water cooling of the anode of hydrodynamic lamps, proving the possibility of creating powerful hydroelectric lamps. In 1923 he created G. l. power 25 kW, and in 1924-25 - with a capacity of 40 kW. Since 1922, under the leadership of Soviet scientists M. M. Bogoslovsky, S. A. Vekshinsky, and S. A. Zusmanovsky, mass production of G. l. In 1930, the Soviet scientist P. A. Ostryakov proposed the design of powerful hydrodynamic l. with forced air cooling. In 1933-34 the Soviets. Academician A.L. Mints and engineer N.I. Oganov developed the first domestic collapsible triode with a power of 200 kW, and in 1956, together with engineer M.I. Basalaev, a collapsible triode with a power of 500 kW.
Lit.: Vlasov V.F., Electronic and ion devices, 3rd ed., M., 1960; Tyagunov G. A., Electrovacuum and semiconductor devices, M. - L., 1962; Tsarev B. M., Calculation and design of electron tubes, 3rd ed., M., 1967.
Yu. B. Lyubchenko.
Generator tubes: a - pentode GU-80 (power 450 Tue, largest diameter 110 mm, height 285 mm); b - GU-91 triode with forced air cooling (power 5 kW, largest diameter 240 mm, height 500 mm); c - triode GK-1A with water cooling (power 200 kW, largest diameter 205 mm, height 880 mm).
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
See what a “Generator lamp” is in other dictionaries:
An electronic tube for converting the energy of a current source into the energy of electromagnetic oscillations. Used in radio transmitters, measuring instruments, induction heating installations, etc... Big Encyclopedic Dictionary- an electron tube for converting the energy of a current source into the energy of electromagnetic oscillations. Used in radio transmitters, measuring instruments, induction heating installations, etc. * * * GENERATOR LAMP GENERATOR LAMP,… … encyclopedic Dictionary
generator lamp- 1. Generator tube*(GL) E. Oscillator tube F. Tube oscillateur Vacuum electronically controlled tube designed to generate and (or) amplify, as well as multiply the frequency of high-frequency oscillations
Which is designed to generate energy from an alternating or direct current into the energy of electromagnetic vibrations.
Generator lamps are used in various radio transmitters, physical and medical radio-electronic devices, measuring instruments, as well as in induction heating installations. Generator lamps are also used in the wave ranges: VHF and shortwave. For such lamps short distances between the electrodes, their terminals are thickened and equipped with low inductances, and the insulating elements are made of materials characterized by low dielectric losses.
In the decimeter wave range, generator lamps have a resonant oscillation system, which relates to the composition and design of a given generator lamp.
Such oscillatory systems are found in metal-ceramic, beacon lamps and resonatrons. Unlike the previous ones in millimeter, centimeter and UHF bands waves, traveling and backward wave tubes, magnetrons and klystrons are used.
A generator tube with a triple number of electrodes - a triode - was first used by A. Meissner in 1913. With its help, the German scientist converted high-frequency oscillations. In Russia, the generator lamp began to be used from the first years of the formation of Soviet power. M. A. Bonch-Bruevich produced in the laboratory of the city of Gorky latest developments. In 1919, he proved the possibility of creating powerful generator lamps by using water-cooled anodes. Through
4 years later Bonch-Bruevich invented a generator lamp with a power of 25 kW, and after another 1.5 years a lamp with a power of 40 kW. Under the leadership of S. A. Vekshinsky and S. A. Zusmanovsky, the production of generator lamps was put into production in 1922. The further period of development of generator lamps is associated with their improvement. In 1930, P. A. Ostryakov was the first to design a generator lamp with forced air cooling. 3 years later, engineer N.I. Oganov and academician A.L. Mints developed the first collapsible triode, the power of which was equal to 200 kW. In 1956, these same scientists, together with engineer M.I. Basalaev, designed a collapsible triode with a power of 500 kW.
Generating lamps differ by the number of electrodes, by radio frequency ranges, by the highest power that the negative charge dissipates, as well as by the design of the cylinder and the characteristics of operation. The number of electrodes varies and is called triode, pentode, tetrode, etc. The anode dissipates low power - 50 W, medium - 5 kW, high - more than 5 kW. The cylinder can consist of glass, metal, metal and glass together, and metal-ceramics. The operation of the generator lamp is divided into pulsed and continuous operation.
Due to the wave range and power produced by the generator lamp, their designs are different and each has a specific feature. Low-power generator tubes operate at a negative voltage of 500 W and are similar in structure to receiving and amplifying tubes. Some part electrical energy The power supply supplied to the generator lamp is generated into useful energy. The other part of the energy heats the anode and is dissipated by it. Generator lamps with medium and high power operate at a negative charge voltage of 20 kW. They use a variety of cathodes and anodes. Tungsten, tungsten thoriated and carbided cathodes are used with heating. The copper anode is cooled by air or water. The anode becomes part of the generator lamp cylinder and is equipped with a special radiator. According to another method, the anode along with the grids is smelted from molybdenum and tungsten, metals that are refractory.
When producing very powerful generator lamps with a power of 500-1500 kW, they are designed semi-collapsible or completely collapsible. Semi-collapsible generator lamps are cooled with water, and in collapsible lamps the air is constantly pumped out with vacuum pumps.
Following:
The main purpose of the generator tube is to deliver maximum useful signal power to the load. The maximum power P in the load resistance R n can be obtained when the greatest current passes through it. If the load is connected to the anode circuit of the lamp, then
where I ma is the amplitude of the anode current; R n - load resistance; I mн and U mн - amplitude values of current and voltage in the load; ζ - anode voltage utilization factor; E a is the voltage of the anode power source.
To obtain a larger amplitude of the alternating component of the anode current, the voltage on the control grid should be varied within wide limits, entering the region of positive voltages on the control grid, which leads to the appearance of significant grid currents. From formula (54) it also follows that generator lamps must operate at high anode voltages.
The cathodes of generator lamps must be the most efficient. For this purpose, oxide cathodes are usually used. However, their use is limited to lamps of low and medium power (up to 1 kW), since at anode voltages above 1.5 kV, due to ionization of the residual gas, oxide cathodes quickly lose emission. Therefore, more resistant film cathodes are used in high-power generator lamps.
The anodes of generator lamps with a power of up to 1-1.5 kW are made of nickel, molybdenum, tantalum. They are often coated with a thin layer of zirconium, which increases the emissivity of the anode and the absorption of residual gases in the lamp. The anodes of more powerful lamps require forced cooling and therefore have a special design, described below. The heat generated at the anode of the lamp is either transferred to the flow of water washing the anode, or carried away by the flow of air blowing over it.
Artificial, forced cooling of the anode makes it possible to produce generator lamps with useful power up to thousands of kilowatts.
The power Pa dissipated at the anode depends on the energy parameters of the circuit:
(55)
where η is the efficiency of the circuit; P - oscillatory power given to the load.
As can be seen from formula (55), the higher the value of η, the lower the value of P a. The power dissipated at the anode should not exceed the permissible one, which is given in reference books for each type of lamp.
Generator lamp grids are made of molybdenum or tungsten. During operation of the circuit, the voltage at the anode changes. When it becomes minimal, grid currents can reach significant values. Therefore, the meshes must have sufficient cooling surface. In particularly difficult thermal conditions, the control grid operates, which is additionally heated by a hot cathode. A heated grid can begin to emit electrons, and a current in the opposite direction will appear, which leads to a change in the operating mode of the lamp. In this regard, in generator lamps the control grid is located slightly further from the cathode than in receiving and amplifying lamps. For this reason, the slope of the generator lamp is small.
In generator pentodes, the third, protective, grid is made much denser than in receiving and amplifying lamps. At zero potential on this grid (when it is connected to the cathode), due to the uneven distribution of the electric field in the plane of its turns, the initial section of the anode characteristic very smoothly turns into a flat part of it.
To reduce thermionic emission and the dynatron effect, the grids are coated with zirconium.
Interelectrode capacitances play a significant role in the operation of generator lamps. The passage capacity C ac is especially harmful. To reduce it, the size of the electrodes is reduced, the leads of the anode and the control grid are spaced out, and shielded lamps are used instead of triodes.
Generator lamps with radiant cooling differ little in appearance from conventional receiving and amplifying lamps. They have only slightly larger dimensions, separated leads of the anode and control grid.
However, when designing high-power generator lamps, difficulties are encountered with removing heat from the grids (especially from the shielding). Therefore, in most cases, powerful generator lamps are manufactured in triode design. With air cooling, triodes with a power of up to 100 kW are produced. Designs designed for high power are usually water cooled.
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Of significant interest are the collapsible designs of housings for high-power generator lamps, which make it possible to replace individual faulty parts of the lamp under operating conditions, reduce the cost of the design and increase the service life of the lamps. Powerful generator lamps ( rice. 44) consist of a copper cylinder, closed on one side; on the other side, a glass cylinder is welded to it. The cylinder is the anode. The cathode and control grid are placed inside it. The copper cylinder is placed in a casing with running water. Rice. 44. Powerful generator triode. 1 glass bottle; 2 - mesh; 3 - anode: 4 - water tank; 5 - cathode; 6 - code. |
Generator tubes designed to operate at ultra-high frequencies (at frequencies above 30 MHz) have a special design due to the need to ensure:
- short flight time of electrons between the electrodes, which is achieved by bringing the electrodes closer together and increasing the voltage on them;
- small interelectronic capacitances and inductances of the inputs (due to reduction in the size of the electrodes and the use of ring inputs for all or part of the electrodes);
- low dielectric losses in the cylinder and lamp base (for this purpose, instead of glass, special ceramics are used).
Types and markings of generator and pulse lamps
Generator lamps according to power are divided into the following three classes:
- low power generator lamps - with oscillatory power up to 20-25 watts. Structurally, these lamps are no different from conventional receiving and amplifying lamps;
- medium power generator lamps - with oscillatory power up to 1 kW;
- powerful generator lamps - with an oscillatory power of over 1 kW.
The most common types of low- and medium-power generator tubes are pentodes and beam tetrodes. Due to the small value of the pass capacitance, CAC pentodes and beam tetrodes can be used in circuits operating at very high frequencies.
The following general marking rules are used in the designation of generator lamps. The letters come first:
- GM - for modulating lamps;
- GS - for generator lamps operating at waves shorter than 50 cm;
- GU - for generator lamps operating in the wave range from 50 to 12 cm;
- GK - for generator lamps operating in a range of more than 12 m;
- GI - for generator flash lamps;
- GMI - for modulating flash lamps.
The number following these letters corresponds to the development number. If the lamp has forced cooling, then the letter B is added at the end of the designation, indicating air cooling, or the letter A - for water-cooled lamps. For example, the marking of the GU-28A lamp means that it is a water-cooled generator pentode that can operate in the wavelength range from 50 to 12 cm.