-1 to +1 amp

[Paul Perry]

At 09:11 AM 3/09/98 +0100, jorgen.bergfors wrote:

>>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? 

input goes to top of 10k pot, also via 10k resistor to - op amp input.
other end of pot to earth.
wiper of pot goes straight to + input of op amp.
10k feedback resistor from output to - input of opamp.

when wiper at top of pot, gain is +1
when wiper at earth end, gain is -1.