Oscillator circuit for ultrasonic cleaning

Abstract

An improved oscillator circuit, adapted especially for use in generating multi-frequency wave patterns occurring within the ultrasonic range, incorporates a transistor base drive network in which an alternate discharge path is used for coupling capacitors already known in circuits of this type. Power losses occurring in the transistors are lessened by employing transistors having reverse base-emitter breakdown voltage ratings that are higher than those conventionally employed. Use of the substituted transistors becomes possible by substituting the mentioned alternate discharge path, to compensate for the lower average discharge current that is known to pass through the base-emitter circuits of the transistors by reason of their higher reverse base-emitter breakdown voltages. The improved circuit in this way reduces power loss and its consequent temperature rise in the transistors and in their base and emitter resistors to increase output power to the accompanying reduction of transistor losses.