QUCS, The Free and Open Source SPICE (Youtube tutorials) - Page 1
Forum section: electronics / general

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 19, 2016, 05:59:29 pm
content: I've been using QUCS to learn some electronics theory, since I don't have a formal education in it. I've started working on a set of Youtube videos to teach other newbies about it.I'd really appreciate constructive criticism of these videos, so I can make them more helpful in the future.https://www.youtube.com/playlist?list=PLJzyCDKi44VHzqo70aPkJy2sWBamVo_d2

author: MK14
author_rank: Super Contributor
timestamp: March 19, 2016, 06:20:28 pm
content: The youtube video(s), seem to have your real life name, in the bottom right hand corner, on some of your screen (desktop) shots.This may or may NOT be what you want.Otherwise, I've had a VERY quick skim through, and LIKE what I have seen!EDIT: On second thoughts. I DON'T think you mind. As your name was/is all over the place, anyway.

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 19, 2016, 07:25:50 pm
content: It definitely is what I want, but thank you for pointing it out!I'm glad you enjoy them - what kind of videos would you like to see next? I'm trying to decide between talking about parameter sweeps and digital simulation.

author: MK14
author_rank: Super Contributor
timestamp: March 19, 2016, 07:42:19 pm
content: Quote from: SilverWingedSeraph on March 19, 2016, 07:25:50 pmThey are BOTH interesting subject/video areas.I guess that "digital simulation", would be best at this stage. As it is more/most likely to be of interest, to a wider audience. But the "parameter sweeps", is something which intrigues me a lot (BUT is probably a minority interest, to MOST people).I've started playing with QUCS today. I'm pleased/inspired by what I have found. But it does seem at least a little bit "quirky", as regards the user interface. So has a partly steeper learning curve, than perhaps other software.Hence I'm hoping your videos will help, push me (and many others), along.I've managed to get a quick schematic going. But can't immediately/quickly see how to plonk the transient analysis thing into it. As it stands it just says, on running "Nothing to do".So I will go back to properly watching your video(s), when I have got more time.Thanks! (The video(s) are raising my interest levels in it, and helping me understand how to use it).

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 19, 2016, 07:44:43 pm
content: Well, perhaps I'll do a more in-depth video on transient simulation first then. Thank you for the advice, and I'm glad you're finding use from the software.

author: janoc
author_rank: Super Contributor
timestamp: March 19, 2016, 08:01:50 pm
content: I have just yesterday thrown my hands up in the air in disgust over QUCS. I was trying to simulate that silly buggy latching on/off circuit that discussed in another thread to verify a few things and QUCS was pretty hopeless there.First random errors with the schematics - it doesn't tell youwhatthe problem is, only that there is something wrong and aborts. Yay ...Then the transient analysis doesn't actually converge because apparently QUCS has issues with handling switchesSo it is back to an older version of EveryCircuit on my tablet for the silly stuff like that and LTSpice for the less than silly circuit for mePity, because the software has promise and there aren't that many free simulators around.

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 19, 2016, 08:15:49 pm
content: Did you report your problems as bugs to the project? If not, please do!

author: Macbeth
author_rank: Super Contributor
timestamp: March 19, 2016, 08:27:31 pm
content: The first circuit with the transformer. Did you mean to short the grounds together on each side? I presume not, but of course all SPICE circuits have to have some path to a 0 GND. What you really should have used is an extremely large resistor (like 10G ohm) between the primary and secondary grounds to simulate leakage I guess. Much like you used a very low resistor to simulate wire resistance on the primary side.

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 19, 2016, 08:35:50 pm
content: Yeah, I realized that after the video was already up. It doesn't really matter for the video, since the point is to demonstrate the paradigm of the software (it's meant for beginners), but I think in my next video, which will be a more in-depth tutorial on transient analysis, I'll mention that. Thanks!

author: SilverWingedSeraph
author_rank: Contributor
timestamp: March 20, 2016, 12:10:25 am
content: New video is here! It's a more tutorial-like look at DC, AC, and transient simulation in QUCS.

author: janoc
author_rank: Super Contributor
timestamp: March 20, 2016, 10:27:53 am
content: Quote from: SilverWingedSeraph on March 19, 2016, 08:15:49 pmActually the issue with the transient analysis is a known problem since at least 2014 if not longer - I have found it in their bug tracker and forum after banging my head against it for a good while. It is a problem with the naive way they have implemented the calculation, lacking adaptive time step around the times when switches change state.The issues with the schematics I didn't really research, didn't have time to hunt that down as it was intermittent.Both of the above were for the stable 0.18, I will try to build the development version and see whether it was fixed.Edit:Well, the current development version from Git does not even build properly, it is complaining about some missing header file. So so much for it.