TLDR I want to make circuits that are connected but independent in Spice.

I am using the Xic graphical editor for WRspice, but I think that this issue isn't specific to the type of Spice being used. What I want to do is this: send an input into my subcircuit, and then take the output of said subcircuit and pass it onto other subcircuits.

Basically: input -> subcircuit1 -> output -> subcircuit2 and onto more subcircuits. My trouble is that when I add anything else to the output location of subcircuit1, it affects the behavior of subcircuit1. Does that make sense? Adding a resistor onto the circuit changes how the circuit behaves.

I want to send an input into a circuit, have that circuit generate an output, and send that output onto the next circuit without the components of the second circuit affecting the behavior of the first. I.e making these circuits independent of each other while being connected. Is this possible?

I hope I am clear. Thanks!


Assuming you want to use the voltage of one as the input of another, could you use a voltage dependent voltage source, with a gain of 1? It won't be a realistic simulation of the circuit, but hopefully you understand that since you're specifically asking for that.

  • \$\begingroup\$ Thank you. I think I get what you're saying. I take it, from you saying this won't be a realistic simulation, that voltage dependent sources aren't a real, practical thing? If so, is there a way to kind of simulate the effects of using a voltage dependent source in a real, physical circuit? \$\endgroup\$ – joe12345 Jul 8 '18 at 2:39
  • \$\begingroup\$ @worm12345823084 An op amp voltage follower is probably your best bet. \$\endgroup\$ – Hearth Jul 8 '18 at 2:40
  • \$\begingroup\$ If you don't want a circuit to load the previous stage you need a buffer between them. \$\endgroup\$ – Matt Jul 8 '18 at 2:40
  • \$\begingroup\$ But in reality, no circuit is truly one way, and connecting the "output" of circuit A to circuit B will always change circuit A. It just depends how much of an effect you can tolerate. Op amp followers add some offset, have finite frequency response, etc. \$\endgroup\$ – Matt Jul 8 '18 at 3:10

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