[sdiy] when to use LIN POTS and when to use LOG?

[David G. Dixon]

Dan,

> i know that LOG are for volume.
> 
> But beyond that, if i am controlling GAIN (or volume) in the feedback path
> of an opamp, is that a log?

If for voltage gain, no.  If for volume, probably.

> and what about a voltage divider that is feeding less or more CV into an
> expo? Would that be LOG? (since it is an AMOUNT?)

No, since the CV into an expo should be linear for the output current to be
exponential.

> what about a voltage divider feeding more or less signal into a section of
> a circuit?

Not usually log.

> and what about TIME? like in a LAG?
> 
> would i use a LOG pot for an attack?

Almost always, yes.

> I was under the impression for example that often times, instead of using
> a smaller value LINEAR POT, the answer might be to use a LOG POT.
> 
> i was messing around with a lag where i Had a 100k pot. it seemed like it
> only LAGGED at the first 10 percent of the pot. but my friend said, thats
> because you need a LOG.
> 
> 
> i think this has remained a mystery to me because whenever i have bought
> pots, i just buy lots of cheap ones. and LIN are make more commonly on
> sale and more widely used.

I believe that one can convert a linear pot to a reasonably close
approximation of a log pot with one or two properly sized resistors across
the terminals.  I'll do some calcs and get back to you with the results.  I
did this earlier this year for some reason, but I might have been going the
other way (log to linear).

> thanks!!!!
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