# multivibrator

Discussion in 'Electronic Basics' started by [email protected], Nov 9, 2005.

1. ### Guest

How is a multivibrator different from an oscillator?
Is it that a multivibrator generates square waves only (two-state)
while an oscillator's output can be any periodic waveform (sine,
square, triangle etc) ?

-Benn

2. ### RichardGuest

Yes, mutivibrators are switching circuits that produce square-wave outputs.
The square wave output can be modified (integrated, differentiated,
filtered) to produce different waveshapes. For instance, integrating a
square wave results in a triangular wave.

Oscillators generally produce sine waves, however, an astable (no stable
state) multivibrator is a square wave oscillator.

Another difference between oscillators and multivibrators is that, with the
exception of the astable multivibrator, multivibrators require an input
signal; oscillators do not.

I hope this helps.

Richard

3. ### Michael BlackGuest

If it's an astable multivibrator, then there's no difference. It's
merely a type of oscillator, it generates a signal.

Michael

4. ### John PopelishGuest

A multivibrator is certainly a kind of oscillator. I think your
distinction is a good one, but change "square waves" to "a pulse
train", since there is no reason to expect a multivibrator to achieve
a square wave output unless you have taken pains to make it do exactly
that. Essentially any duty cycle is possible.

5. ### Paul BurridgeGuest

Hello, John. Nice to see you're still imparting your invaluable wisdom
to students of this most technically-challenging of hobbies.
My 2p worth...
A multivibrator is a form of (RC) oscillator, but one which by its
very nature is guaranteed to self-start and produce a squarish
waveform. Conventional LC oscillators require a noise shock and
adequate positive feedback to get going. Then they'll ordinarily
generate a sine wave.
No doubt someone will find fault with that distinction, though. :-/