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From: raoul@eplunix.UUCP (Nico Garcia)
Newsgroups: sci.electronics
Subject: Re: Good Clamping Circuit
Message-ID: <1041@eplunix.UUCP>
Date: 9 Mar 91 22:02:55 GMT
References: <1991Mar06.181426.10500@cdsmn.mn.org>
Organization: Eaton-Peabody Lab, Boston, MA
Lines: 26

In article <1991Mar06.181426.10500@cdsmn.mn.org>, plate@cdsmn.mn.org (Doug Plate) writes:
> *----------------------------------------------------------------*
> I'm looking for a simple circuit that will clamp the output of a summing
> amp to 5 volts.  The circuit uses an OP amp in a non-inverting
> summing configuration (unity gain) with 2 inputs, either of which 
> can go from 0 - 5 volts, however the  output must come up to 5 volts 
> and stop (plus or minus about .009v) even if the sum of the two 
> input > 5 volts.  

Ummm, like this?
                    -----------------
                    |  |\            |  
                    ---|- \          |
                       |    \        |
V1--------R1----|      |      \______|  Vout
                |------|      /
V2--------R2----|      |    /
                       |  /
                       |/

Why not just use a good 5 Volt supply op-amp, with rail-to-rail capability?

-- 
			Nico Garcia
			Designs by Geniuses for use by Idiots
			eplunix!cirl!raoul@eddie.mit.edu