Same source OP-AMP summing/adder circuit?

[elRey]

Say you have multiple circuits running off one battery (+12v).

Say the output of circuit #1 oscillates about +1.5v amplitude of 1v. (+1v - +2v)

I can't modify circuit #1. But I want to press a button, and while that button
is pressed down, offset the output of circuit #1 by +1.5v. (+2.5v - +3.5v)

Can this be done using the one battery used for all circuits?

Thanks,
Rey

 

[Ulisse]

I'm sorry for my bad english but i'm Italian....

you can adjust the offset by plugging the voltage offset to the offset pin of an Operational Amplifier with gain=1

or you can build an Adder with an Operational Amplifier..

you can plug the inverting input with a resistor=1K to the ground, the out pin to this pin (feedback resistor) with a resistor = 1K and at the non inverting input you can plug your signal by a 330ohm resistor and the offset signal with an other 330ohm resistor (both resistor have a pin plugged to the same pin of the IC)

 

[Russlk]

This is how I would do it: