KiCad models and simulation - Page 1
Forum section: electronics / general

author: perdrix
author_rank: Frequent Contributor
timestamp: February 08, 2022, 10:27:28 am
content: I've entered a circuit using the schematic editor, and I want to simulate it, but AFAICT none of the parts has an associated model! Do I need to find/create models for every component in my design and add them by hand to each part one by one? Surely not.I'm trying to migrate from "another" package that always adds the model data when you place a part. There may be multiple models available for a part (or only one), but at least the spice models are there.Am I missing something obvious?D.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: February 08, 2022, 12:45:27 pm
content: http://ngspice.sourceforge.net/modelparams.htmlfrom:https://forum.kicad.info/t/where-do-i-find-models-for-ngspice/29485/3

author: thinkfat
author_rank: Unknown
timestamp: February 08, 2022, 04:44:01 pm
content: You got that right. There are no models shipped with with KiCAD. If you want to simulate a circuit, you need to add the models yourself. Spice or XSpice models are usually fine.

author: perdrix
author_rank: Frequent Contributor
timestamp: February 08, 2022, 05:24:11 pm
content: Good grief! That's more than a minor pain.For a circuit with four or five parts it might just about be tolerable, but when there are hundreds - not so much.I'd really liked it up to that point - large component and footprint library, quite useable UI etc..Yeah I know - I don't have to use KiCad. And that may be what stops me.D.

author: ataradov
author_rank: Super Contributor
timestamp: February 08, 2022, 05:49:59 pm
content: Schematics for simulation and schematics for manufacturing are typically very different. Merging them in one tool is bound to fail on both sides.This is just no the right approach, that's why it does not work.Also, attempting to simulate a full schematic is likely to be painful anyway. Simulate small sub-circuits that matter.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 08, 2022, 06:29:48 pm
content: Agreed.

author: TimFox
author_rank: Super Contributor
timestamp: February 08, 2022, 07:44:28 pm
content: I admit to being old-fashioned and that I keep to ways that work for me. Those not interested need not follow my recommendation.Therefore, I persist in using line-oriented Spice (not schematic capture), especially for .AC mode to calculate frequency response of linear circuits.Often, I draw my simulation circuit using KiCad, to label the nodes and component references before manually generating the circuit file.My software is AimSpice, which is available in a free student version.http://www.aimspice.com/It's post-processor is efficient: I use it to generate .csv files that I then graph with Grapher (from Golden Software), which is rather expensive but I learned to love it at work before retirement, since it produces "literate" graphs with the format under my control.Spice files for common semiconductors and analog ICs are often available from the manufacturers' websites.

author: hvogt
author_rank: Contributor
timestamp: March 16, 2022, 09:35:08 pm
content: I do not agree.You may very well use the same tool (e.g. KiCad/Eeschema/ngspice) for production schematics and simulation schematics.And I also can't imagine that it does make sense to simulate a circuit with "hundreds" of different devices with hundreds of different models (we do not talk about reistors and capacitors here).Model parameters and models are available here:http://ngspice.sourceforge.net/modelparams.html.

author: simon mugo
author_rank: Contributor
timestamp: March 31, 2022, 02:20:05 am
content: you are very correct. KiCAD does not ship in with its models when you download. You have to customize the models. For the simulation part, you need to look at the xspice modes and install them into your KiCAD version.All the best.

author: hvogt
author_rank: Contributor
timestamp: April 01, 2022, 03:34:41 pm
content: Inhttp://ngspice.sourceforge.net/ngspice-eeschema.html#BipAmpyou will find a description how to add a model (for the BJT) and start the simulation, inhttp://ngspice.sourceforge.net/ngspice-eeschema.html#OpAmpthere is described how to do this for an operational amplifier.Inhttps://forum.kicad.info/t/simulation-examples-for-kicad-eeschema-ngspice/34443you will find several examples for simulating circuits. These are projects ready for simulation if you have installed KiCad 6.0.4 (including ngspice-36).