Hi, Ste - Yes, I have now reviewed the manual and understand the time step information. Regarding the SPICE simulation, I guess it’s good to have an idea of what results you expect, and then try different time steps to ensure that the solution is indeed converging to a real solution, yes?
When you run simulations, do you normally put the time step information on the schematic in a text box?
Or do you typically place that information somewhere else that gets in the “netlist”?
Is there a “rule of thumb” regarding step size that can be calculated from some of the
circuit parameters?
The software is outstanding, very easy to get started! I’ll keep working with sample circuits to
better understand the workings of the software and electronic design theory.
Yes, you always need some sort of idea beforehand so you can distinguish between reasonable and bogus results.
That’s what I typically do, since you have the most control that way and also makes the netlist more portable (such as pushing it to an external SPICE engine). The UI in the Simulator app doesn’t let you specify tmax, but if you set tstep small enough it will automatically use that instead.
The smallest possible is the goal, since there’s a tradeoff in simulation speed from specifying low tmax values. It really depends on how long your simulation is and what kind of details you’re looking at. If I have a 1KHz sine wave exciting a circuit, I would probably want to ensure at least 100 points are calculated within one period…so maybe I would try setting tmax to 10u in that instance.
Ste - It’s all working great now. Your explanations really helped a lot! I am able to make
small changes to see the effect on the pulse width at the solenoid and pick the right component
values. It’s such a little solenoid and such a simple circuit, but it’s got a ton of details that have
been very educational. I bought parts for my “simple cap & resistor” circuit, and also for this
more complex “cap, transistors & resistors” circuit. It’s going to be a lot of fun to build them on
stripboard and to watch them work!
Hopefully the next time I run into trouble, it won’t be such a newbie issue!