OT: PSpice problems

[Jason Stout]

I am hoping someone will see why PSpice doesn’t like this circuit. There must be a way to simulate this circuit, and all the other discrete active filters I have tried, I just don’t know how! The ‘floating’ nodes are in the filter.

Just thought I’d ask.

[Brett Clark]

PSPICE doesn't like it because there is no DC path to ground for those nodes.

Tie one of those nodes to ground with a 10 Meg resistor or something. It won't affect the results, except to make it work.

As Bob Pease would say, this is just one of the 1,001 ways that SPICE can ruin your day! Never use the stuff myself...

[Jason Stout]

Thanks Bret! both you and Bob Pease are correct. I'm off to find the other 1000 ways.