[sdiy] opamp protection resistors

[Neil Johnson]

Hi David,

> Will it affect filter performance in any way if I simply slip 100R  
> resistors
> in between the opamp outputs and the feedback junctions of the  
> integrators
> (note: C = 200pF), and take the filter outputs directly from the  
> feedback
> junctions?


So, if I understand correctly, you now have a naked connection from a  
high-impedance node (your feedback junction) to the outside world.   
What would happen if you plugged an output into your output?  Would  
your op-amps latch-up?  Go into phase-reversal?  Or what might happen  
if you short your output to ground, which will happen when plugging  
in a jack lead from one of your outputs into an input socket?

Simulation is fine to a point, but not so good on the realities of a  
circuit's existence :)

Cheers,
Neil
--
http://www.njohnson.co.uk