Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!ncar!boulder!sunybcs!rutgers!bellcore!texbell!merch!cpe!hal6000!trsvax!jim
From: jim@trsvax.UUCP
Newsgroups: sci.electronics
Subject: Re: Op amp gain control
Message-ID: <190700033@trsvax>
Date: 15 Feb 89 18:16:00 GMT
References: <100@PSUVM>
Lines: 10
Nf-ID: #R:PSUVM:100:trsvax:190700033:000:478
Nf-From: trsvax.UUCP!jim    Feb 15 12:16:00 1989


I've seen someone use a quad analog CMOS switch (4066?) to switch a
couple of resistors hooked-up like an R-2R DAC in the feedback loop.
This will take fewer resistors than the 4053 and such for anything
over 3 bits or so. It also works on capacitors in analog filters and
oscillators if you are willing to search for nore-or-less exact values.

If you need an explaination of an R-2R DAC, send mail, I'll reply.

James T. Wyatt   UUCP:decvax!microsoft!trsvax!rwsys!jim  KA5VJL