Oscillator Tube

an electronic tube for converting the energy of a DC or AC source into the energy of electrical oscillations. Oscillator tubes are used in radiotransmitters of various designations, measuring devices, radioelectronic devices of experimental physics and medicine, induction heating devices, and the like. Oscillator tubes are distinguished by their radiofrequency range, number of electrodes (triodes, tetrodes, pentodes, and so on), maximum power dissipated by the anode (low power is up to 50 watts, average power is up to 5 kilowatts, and high power is above 5 kilowatts), mode of operation (continuous or pulse), construction of the container (glass, metal, metalloglass, metalloceramic), and other factors.

Oscillator tubes have a number of special constructional features associated with generated power and frequency range of waves. Low-power oscillator tubes operate at anode voltages up to 500 volts and are constructionally similar to radio-receiving tubes. The electrical energy supplied to the oscillator tube from the power source is only partially converted (up to 70 percent) into useful energy (oscillatory) and the rest is used up and dissipated in heating the anode; therefore, in average-power and especially in high-power oscillator tubes operating at anode voltages up to 20 kilovolts, a cathode with direct warm-up (thoriated tungsten, carbidized or pure tungsten) is used, and the grids and anode are made of a refractory metal (molybdenum, tungsten). There are also copper anodes (in oscillator tubes with forced air or water cooling at rated dissipation power of more than 1-3 kilowatts). For air cooling, the anode is made as part of the oscillator tube container and is equipped with a radiator and blown out with air. The most powerful oscillator tubes (500-1,500 kilowatts) are demountable (with continual vacuum pumping of air) or semidemountable with forced air cooling. The oscillator tubes used in high- and very-high-frequency ranges have small interelectrode distances, reinforced low-inductance electrode terminals, and insulated elements made of materials with small dielectric losses. In ultrahigh-frequency oscillator tubes, the resonant system is a part of the tube’s construction (metalloceramic tubes, lighthouse tubes, resnatrons, and other types). In decimeter, centimeter, and millimeter wave ranges, special oscillator tubes are used, such as klystrons, traveling-wave tubes, backward-wave tubes, and magnetrons.

In 1913 the German scientist A. Meissner first used a triode to generate high-frequency oscillations. In the first years of Soviet power, the most important development work on oscillator tubes was done under the direction of the Soviet scientist M. A. Bonch-Bruevich at the Nizhny Novgorod Laboratory (in Gorky). In 1919 he first used water cooling of the oscillator-tube anode, making possible the creation of powerful oscillator tubes. In 1923 he created a 25-kilowatt oscillator tube and in 1924-25 a 40-kilowatt tube. Since 1922, under the direction of Soviet scientists M. M. Bogoslovskii, S. A. Vekshinskii, and S. A. Zusmanovskii, a large-scale oscillator-tube industry has been operating. In 1930 the Soviet scientist P. A. Ostriakoy proposed a high-power oscillator tube with forced-air cooling. In 1933-34 the Soviet academician A. L. Mints and engineer N. I. Oganov developed the first domestically made demountable triode (200 kilowatt), and in 1956, together with engineer M. I. Basalaev, they developed a 500-kilowatt demountable triode.