Simulation gotchas

[glennra]

Hi,
I’ve been trying to figure out how to do simulations in Kicad. After a fair bit of trial and error and comparing with examples I’ve managed to get a simulation of the following circuit running.

This is just a replication of Electroboom’s slayer simulation.

I got the models for the 2N2222 and 1N4148 from the Kicad-spice-library on github.

There were a few things that are not all that obvious that I had to do:

• Swap the pins on the transistor to 2 1 3.
• Swap the pins on the diode to 2 1.
• Pay attention the inductor pin connections to get the correct polarity.

Are there any other non-obvious things that I might need to know about for other simulations? I have some experience with LTSpice and I’d probably be an advanced beginner.

Also: If I change the values in the the .tran directive how do I get the simulator to pick that up without closing and re-opening it?

[paulvdh]

There are a bunch of working examples in:

More simulation examples for KiCad/Eeschema/ngspice

New simulation examples are following here. This time I am using KiCad 7.99. The new simulator interface is offering a lot of enhancements, which make it absolutely worthwile to have a look at this development. ngspice-41 is typically involved. Sometimes I am using ngspice-42 to benefit from the ngspice improvements. The previous examples (KiCad 6, ngspice-38) are visible at Simulation examples for KiCad/Eeschema/ngspice . The examples provided should run out-of-the-box: Extract the *.7z file…

Simulation often is quite finicky to get going, and starting with something that works is a big benefit.

But it’s an old topic (over a year now) and therefore I’ll close it.