Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!labrea!rutgers!caip.rutgers.edu!wolpert From: wolpert@caip.rutgers.edu (Seth Wolpert) Newsgroups: sci.electronics Subject: Re: Op amp gain control Summary: A suggestion that has worked for me. Message-ID: Date: 14 Feb 89 16:12:05 GMT References: <71213ART100@PSUVM> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 24 In article <71213ART100@PSUVM>, ART100@PSUVM.BITNET (Andy Tefft) writes: > Probably a simple question, but: > > I want to be able to control the gain of an opamp by an external control. > that will do this for me? > > Andy Tefft > There is a CMOS device called an analog multiplexer that includes; 4051 triple 2-1 analog multiplexer, 4052 double 4-1 analog multiplexer, and 4053 single 8-1 analog multiplexer. All three are controlled from a CMOS-compatible binary source, and offer a very low parasitic resistance, especially when powered with a 15-volt supply. They are inexpensive and very available. I have used them in several projects with good results. They can be banked if more than eight settings are required. If you need any details, please let me know. I'd be happy to elaborate. Seth Wolpert ******************************************************************** SW** I LOVE mankind-it's PEOPLE I can't stand! Linus Van Pelt **SW ********************************************************************