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EEVblog => The AmpHour Radio Show => Topic started by: Pat Pending on March 09, 2012, 08:55:08 pm

Title: The Amp Hour #85 - CircuitLab Discussion
Post by: Pat Pending on March 09, 2012, 08:55:08 pm
I find spice simulators useful for checking analog filter component variations and for certain lowish frequency RF queries.
So the on-line CircuitLab spice simulator sounded interesting and worth kicking the tires.

I sketched an RC circuit comprising the following 3 items, 1V DC,  100R and 1uF and ran an time domain simulation for 1 second with a step size of 1us.

The estimated time for compute was 5mins, but time seemed to get dilated the longer I waited - then in the end, a script error and no plots.
Something is badly broken here, for this is simply many orders of magnitude too slow for only 3 components.

Anyone else have better luck with this?
Title: Re: The Amp Hour #85 - CircuitLab Discussion
Post by: Bored@Work on March 09, 2012, 09:21:22 pm
I am not sure it is a real spice at all.

Emphasis by me
Quote
SPICE-like models with a mixed-mode simulation engine

Sounds more like they use an own simulation engine.

I played a little bit with it, and I did get the expected results for my trivial circuits, no crashes. Although I didn't manage to figure out how to get a reading from the voltmeter element they offer under Unsorted Elements. But selecting a net with the cursor worked to read the voltage.

But all in all, I don't see the point in having an online simulator. I am showing my age here, new and different doesn't automatically mean better. If you look for a free-of-charge, although proprietary SPICE, then LTSpice  is worth a try.
Title: Re: The Amp Hour #85 - CircuitLab Discussion
Post by: Pat Pending on March 11, 2012, 04:15:27 pm
I agree B@W, this on-line spice simulator is more of a distraction rather than a useful tool I could seriously use.

Ltspice comes pre-installed with only Linear Tech parts but at least the editor does not prevent the export of a general spice netlist, and that opens up the door to other engines such as Ngspice.

Two more engines worthy of mention (in particular for the RF inclined) are Qucs and Ansoft's DesignerSV.