Analogue adder circuit

Jan 17, 2007 7 Replies

Hi, can I know where to get a analogue adder circuit thanks.



On a sunny day (17 Jan 2007 06:39:44 -0800) it happened snipped-for-privacy@gmail.com wrote in :

2 resistors.

Jan Panteltje a écrit :

That one will also divide by 2 for free.

If the OP really wants an adder he'll need one opamp and 2 Rs more.

Thanks, Fred.

On a sunny day (Wed, 17 Jan 2007 16:28:09 +0100) it happened Fred Bartoli wrote in :

Depends, if he feeds the 2 R into a low impedance point he adds current just fine without dividing. It is all ration and error allowed.

1M and 1M into your uA meter (1k impedance perhaps) adds with .1% error.

IN+ to GND, the 2 Rs from input sources to IN-, one more R from there to OUT. Saves 1 R or about $0.008 fully burdened :-)

Ok, it also inverts.

SCNR, Joerg http://www.analogconsultants.com

I bet you build your instrumentation amplifiers using the two op-amp approach rather than the better-known three op-amp approach too, right? :-)

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Nope, with the two-transistors-glued-together approach :-)))

Regards, Joerg http://www.analogconsultants.com

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