oscillator In physics, a device for producing electrical oscillations (vibrations), such as sound waves, as in a sonar or an ultrasonic generator. In electronics, an oscillator circuit converts direct current (DC) electricity into high-frequency alternating current (AC).

oscillator An electronic circuit that switches back and forth between states. Oscillators are mainly used to provide clock signals or a frequency reference, in which applications they are normally crystal controlled. A specialized form is the VCO (voltage controlled oscillator) in which the frequency may be modified within limits by a control voltage, the free-running frequency being determined by external components.

oscillator. That part of electrical generator which produces a repetitive waveform. The term is sometimes used to mean the whole generator.