Stabilotron Tube

a frequency-stabilized, mechanically tunable microwave oscillator consisting of a platinotron and a feedback circuit (Figure 1). Feedback is obtained through a partial reflection of the energy of the microwave oscillations that are excited in the platinotron by a power divider (from one side) and through the reflection of energy by a cavity resonator (from the other side). The resonator reflects energy only at its resonant frequency, with the energy of the oscillations at all other frequencies being passed into an absorber. The frequency of the resonator can be changed by moving a plunger. Maximum power output at each frequency is obtained through the fine tuning of a phase shifter.

Figure 1. Schematic diagram of a stabilotron tube: (1) platinotron, (2) direction in which the platinotron amplifies oscillations, (3) controlled phase shifter, (4) absorber, (5) stabilizing cavity resonator with high quality factor. (6) resonator plunger, (7) power divider, and (8) direction of the flow of microwave energy

In comparison with a magnetron, frequency drift in a stabilotron tube caused by changes in service load, platinotron anode current, and ambient temperature is lower by an order of magnitude. Although the applications of stabilotron tubes are similar to those of magnetrons, the former are used less often because of the inconvenience of tuning the frequency with two control members.