[sdiy] Is this a comparator?

[René Schmitz]

Hi Derek and all,

Derek Holzer schrieb:
> There's a function I want to implement, but I don't know what to call it 
> so I can't start researching the right circuit.
> 
> I'd like to compare an incoming voltage with a reference voltage, and 
> only allow the incoming voltage to pass if it's above the reference 
> voltage. I do not want to square the signal, I want to pass it unaltered 
> so long as it's above the threshold of the reference voltage. When the 
> incoming voltage is less than the reference, then the reference voltage 
> would be passed (or none at all).
> 
> What is this function called? A comparator? A gate? It's not a logic 
> function, since it doesn't deal with square waves. I imagine it's a 
> simple op-amp trick...
> 
> thx + best,
> d.

That would be a maximum circuit.

A very simple one can be found on my website:
http://www.uni-bonn.de/~uzs159/minmax.html

Cheers,
  René