What does an oscillator do?

Answer 1

Oscillators are used in a lot of applications. The fact that they oscillate, meaning switch between a zero and positive orbetween a negative-positive value in a repetitive way, makes them useful as a time base.

As time base, they can be used to activate processes that are time-dependent, eg. a computer: has an internal clock (several, to be more corect) that is driven by a kind af an oscillator.

Most of these oscillators to drive time-based electronics are digital, meaning the oscillation is a square wave between 0volts and some positive value (eg. 3.3V or 5V)

Another common use of oscillators is for data communication: a waveform of a certain frequency is generated by an oscillator, and information is superponed on this electromagnetic wave.

Other appliances that use waves generated by oscillators are like microwave ovens, radar, sybthesizer, clock radio, modem (both digital and analog types), sirens, Christmas lights, ...

You can be sure, if it has anything complicated electronic in it, it almost certainly has an oscillator build in.

see also http://en.wikipedia.org/wiki/Oscillation

Answer 2

An oscillator, well, oscillates. It generates a continuous time-varying signal, usually a sinusoidal waveform, but it could be anything, such as a sawtooth, triangle, or pulse train.

The harmonic oscillator works by having some kind of amplifier sitting in a feedback loop with a tuned circuit, often simply an RC, RL, or RLC filter or crystal, and the output is a sine wave.

The relaxation oscillator works by having a capacitor (sometimes an inductor) coupled with a non-linear switch that periodically charges and discharges, and the output can be pulse, sawtooth, or triangle, as needed.