Simple op amp question

[sasami at blaze.net.au]

You will not achieve what you want doing this. Followers 
opperate with the signal fed into the non-inverting input. 
Inverters have it going in the inverting input.

All that will happen when the proposed switch is thrown is 
the output of the opamp will "follow" the voltage on the 
grounded non-inverting input, swamping the signal 
fed into the inverting input, effectively reducing the 
output to zero. Pots are often put in the position you 
suggest for the switch to control gain.

Ken

>A simple op amp question:
>
>OK, I am looking at an existing circuit here and not 
starting something from
>scratch.  Let's say I have an op amp wired in a simple 
inverting fashion
>with the input resistor and feed back resistor sized the 
same providing
>unity gain for the sole purpose of restoring the proper 
phase from a
>preceeding inverting stage (like a summming amp).  It 
appears to me (I have
>not tried it yet) that a simple switch wired from the 
inverting input to the
>output (shorting out the feeback resistor) could serve as a 
phase reversal
>switch effectively bypassing that unity gain inverting amp.
>
>Am I thinking right?  It has been my practice to short the 
unused amp in a
>dual in this fashion if it is not part of the circuit.  So, 
I cannot see why
>this would hurt the amp.
>
>As always, thanks for the help
>
>Larry (still learning slowly) Hendry
>