[sdiy] Op Amp Question (new ascii schem)

[Stewart Pye]

  Hopefully this comes out better...



                 |---------////22k////------------|
                 |                                |   
                 |                                |               
OP amp 1 Output --- ////22k//// |                 |
                                |                 |         
                                |--analog switch ----Op Amp inverting input
                                |
OP amp 2 Output --- ////22k//// |



I have a circuit where I want to switch two additional inputs to an op 
amp summing circuit using an analog switch. So that I can get away with 
using just one analog switch I had the idea of joining the summing end 
of the resistors together and have an analog switch between there and 
the summing node.


My question is when the switch is in the off position we are left with a 
44k resistor between the two op amp outputs. Would this cause any bleed 
from one output to the other, or does the low output impedance of the op 
amps eliminate this?
When the switch is off I want only the op amp 1 output ( with half the 
gain of when the switch is on) but don't want any bleed from op amp 2 
output...

Cheers,
Stew.












Andre Majorel wrote:
>>     
>
> Stewart,
>
> FYI your schematic is unreadable here. Always switch to a fixed
> spacing font before attempting ASCII art.
>
>