[sdiy] Comparator = Opamp ??

[Jim Patchell]

    You can use an op-amp as a comparator, but, in general, you cannot use a comparator as an opamp.  Internally, the front ends are pretty similar, differential amplifier, etc, but the outputs are quite different.  Comparators are generally optimized for
maximum speed.  For low speed applications, I will use an opamp if there is one on the board.  High speed operations you are better off with a part made for the job (a good example is the comparator in a VCO circuit).

    -Jim

Peter van Hamersveld wrote:

> A comparator is a digital device that outputs a 'high' signal (logic 1 or about 4 to 5 Volts), when the voltage on the + connector is higher than the voltage on the - connector. If the one on the + is lower, it outputs a 'low' signal (logic 0 or 0 Volts).
>
> An Opamp has exactly the same appearance in schematics, though i get the impression (from Circuit Maker 2000 (simulation software)) that it behaves differently. Can anyone tell me the difference, or state that they infact ARE the same...
>
> tnx, thanks, tanx, thanx, tanks, tnks, thnks   (choose your favo-spelling)
> -- Peter van Hamersveld, plons at gmx.co.uk on 06-03-2001