Design of Self-Limiting Transistor Sine-Wave Oscillators

By combining the describing function approach with a large signal transistor model and certain simplifying assumptions, it has been possible to develop a set of universal curves yielding selflimiting operating amplitudes for a large class of transistor sinewave oscillators. The variable parameter in this presentation is the dc voltage drop across the emitter bias resistor in the circuit with oscillations absent. Since this parameter may be easily calculated, the material presented allows the design of oscillators for any allowable operating amplitude. In a companion paper the method is extended to include collector saturation limiting and calculations of the onset of squegging.