Oscillators

Abstract

An oscillator is an instrument for producing voltages that vary in a regular fashion; the waveforms of the voltages are repeated exactly in equal successive intervals of time. In many cases the waveform of the output voltage is sinusoidal and the oscillator is then called a sinewave generator or harmonic oscillator. Those instruments that produce repetitive waveforms that are square, triangular or sawtooth in shape are called relaxation oscillators. The term ‘relaxation’ is used because during the generation of the waveform there is a period of activity in which there is a sharp transition from one state to another. This period is then followed by a relatively quiescent one, after which the cycle is repeated. Several examples of relaxation oscillators occur in nature, the most common one being the heart. During the operation of the heart there is a period of activity in which the blood is pumped through the heart chambers and out into the arteries. This period is followed by one in which the heart muscles relax and prepare for the next burst of activity.