[sdiy] Is this a comparator?

[Tom Bugs]

Hiya D

Yeah, you want a comparator first and then use the output squarewave of 
the comparator to open/close an audio switch (4000 series or DG one for 
decent bipolar).
Depending on the app you may need some hysteresis or smoothing on the 
comparator -- are you treating audio or control signals?

Rocking'n'best,
Tom

Derek Holzer wrote:
> 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.