I noticed and got surprised by this too, when simulating the following curcuit:
using the corresponding BJT models from
I had simulation results for the PNP BJT base in the kV range. The result seems to depend on the simulation step duration too. Running the simluation for 3s with different step durations:
- With 1ms step duration I get 150kV overshoot
- With 10us step duration I get 28V overshoots
- With 1us step duration I get no overshoots (result is always in the expected 0-8V range
The problem with shorter step durations are simulation time (understandable) and GUI slowdown for zooming and panning.
As a comparison with a Spice based Windows circuit simulator for the same circuit simulation I get the expected result without overshoots with a 1ms step duration. I’ll try to track down the reason for the difference with the .listing trick someone pointed to here earlier.
I’m a newbie with simulation and Spice/KiCad in particular; could someone explain the reason for this behavior and if there is a way to resolve it (besides short step durations which make the GUI slow)?
Btw, thanks to the Cern team for this new simulation feature, I’ve been long looking for an integrated simulator I could run on Linux.