[sdiy] Opto-transistor question

[Harry Bissell]

we say "barking up the wrong tree"

Either the transistor or darlington type optocouplers are mostly specialized for switching applications.

There is a FET optocoupler H11 something (someone else will tell you the number) that has been used
with some success, although like most FET VCAs it has a kind of limited signal input range.

You also want to look at Avago technologies, who make a large number of optocouplers that could easily be suitable for a VCA, although they
are probably not either cheap or easily available.

I'd also check the list archives, look for optocoupler and that should get you there...

Good luck !

H^) harry



----- Original Message -----
From: Harlan Foster <harlan.foster at gmail.com>
To: Synth-diy at dropmix.xs4all.nl
Sent: Wed, 14 Mar 2012 15:50:06 -0400 (EDT)
Subject: [sdiy] Opto-transistor question

Hello all, I've been diving into the SDIY thing for a few years now,
but I'm still kind of wet-behind-the-ears. Recently I picked up some
opto-transistors (4N32 & 4N36), I was thinking that they may come in
handy. I've been breadboarding with them trying to cook up a simple
VCA, but I've not had any success.

I'm shooting for something simple, I don't mind if the results are
less than ideal. Am I barking up the wrong cheese? Can anybody point
me  in the right direction? I have several transistor based VCA
schematics that I have built in the past, but this has me stumped.

Thanks for the knowledge you all share in this forum, I really enjoy
this mailing list!
>Harlan
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-- 
Harry Bissell & Nora Abdullah 4eva