An Amplitude Stabilized Transistor Oscillator

This paper describes an audio-frequency oscillator using two junction transistors in push-pull Class C operation. The circuit features an over-all efficiency as high as 75 per cent, low distortion, signal-to-noise ratio better than 100 db, and a high degree of amplitude stability. The amplitude can be held to the order of one per cent over wide ranges of supply voltage, output loading, and temperature. The stabilization is achieved by comparing the output amplitude with a reference voltage, which is obtained by means of the so-called break-up effect in semiconductor p-n junctions. An analysis of the circuit is appended.