2/4 quadrant multiplier theory

[List, Christopher]

Yes, I love this trick. You can find this circuit used in just about
everything I build, and you can find it on the www here;

http://www.mindspring.com/~clist/resource/circuits/LM1036Mixer.html#Sche
matics

...Just scroll down a little bit. This circuit has a CV scaled from -1
to +1, and then summed with a constant value from a pot of -15 to 0
(this gets inverted by the summer).


C.List
chris.list at sc.siemens.com

> -----Original Message-----
> From:	jorgen.bergfors at idg.se [SMTP:jorgen.bergfors at idg.se]
> Sent:	Thursday, September 03, 1998 4:12 AM
> To:	pfperry at melbpc.org.au; synth-diy at mailhost.bpa.nl
> Subject:	Re: 2/4 quadrant multiplier theory
> 
> >paul perry melbourne australia
> 
> >BTW, there is a ckt in Horowitz and Hill 'Art of Electronics'
> >that shows how to vary the gain of an op amp stage from 1 to -1,
> >with a pot, which I found VERY HANDY for cv inputs..
> 
> What is this circuit like? Is it an inverting amplifier with unity
> gain where 
> you connect one end of a pot to the input and the other to the output?
> The 
> wiper then outputs a signal that goes from 1 to -1 gain.
> Or is it something more clever?
> 
> /Jorgen
> 
> 
> 
>