Assistance with SPICE Simulations

[JMB]

I have TINA from Texas Instruments and SWcad. I would like to model a circuit to evaluate notch circuits and the effects of components. I am having trouble inserting a voltage source. Every time I try to run a simulation, it insists that I insert an IC into the circuit.

I was hoping that someone might be able to walk me through setting up a simulation in a SPICE program. I am SPICE naive.

Any SPICE freeware guidance would be fine if you aren't familiar with the SPICE programs above.

Thanks,

J

[JohnG]

A complete walkthrough is more than can do at this time, but here are some helpful hints:

Make sure that there are no ideal capacitors in parallel with ideal voltage sources, and that there are no ideal inductors in series with current sources. At the very least, you should add a small resistor (0.001 ohm is a good place to start) in series with voltage sources and a large resistor in parallel with current sources (1e6 to 1e9 is a good place to start.

Also, make sure that every node has some DC path to ground. Things that can form a DC path are voltage sources, inductors, and resistors. If there is a node without such a path, you can add one with a large value resistor (see above).

Finally, make sure you have a ground node.

I use SWcad for home and professional use. There is an unofficial user group on yahoo for it as well.

P.S. If you attach a SWcad schematic to your message, it would help to eliminate any obvious problems.

John

[JMB]

Thanks, I joined the users group, got a manual and also got some other feedback. With the use of your feedback in addition to the other information, I should be good to go.

Thanks again,

Jay