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Thanks, Andy, this helps. The noise (I recently got some scope traces) appears to be uncorrelated to anything like the SMPS, but more likely environmental, within the equipment. Without a spectrum

Dave, If you want to study the effectiveness of adding filters to reduce SMPS noise, you could use a B-source with rand(x), random(x), or white(x) to mimic a "typical" SMPS.? When simulated

If what you want to do is make a substitute model that also generates semi-random noise, and if you want to do that in the time domain, then I refer you to LTspice's rand(x), random(x), and white(x)

I node there was something wrong. More data, please. Is this a physical SMPS, or a design, or a simulation? I guess it might be physical, in which case SPICE simulation may not be of much help. An

I recommend examining the subcircuit models for LTspice's built-in UniversalOpamps, found in UniversalOpamp.lib.? Pair that with the symbols for each UniversalOpamp to see the typical parameter

The OTA is not a simulation mode.? It is a device. Think op-amp, but with a current output instead of voltage.? That's an Operational Transconductance Amplifier. It happens that many OTAs in real

Reposting with the right Subject spelling! Sent: Friday, February 21, 2025 11:54 AM To: [email protected] Subject: EXTERNAL: [LTspice] Node modelling I just got tasked with trying to characterize (and

I just got tasked with trying to characterize (and filter) a noisy switch-mode power supply, There has been some chatter here about noise generation over the years, but one simulation mode I don't

Yes. SPICE (and by extension LTspice) adds GMIN and others such as GSHUNT, GFARAD, and GFLOAT wherever they are needed, and that is done internally and they do not appear in the netlist.? That's just

I'm sorry, but that question does not make sense. The photo does not show a symbol menu.? It is a photo of your auto-generated symbol.? If you want to not use the auto-generated symbol, then do not

BTW, I checked the "Add GMIN across current sources" checkbox in Control Panel. However I can't see anything added or changed in the netlist (SPICE Netlist). Is that a sort of LTspice "internal"

Andre, Not driving any device, monitoring outputs to determine what the input voltage levels are. Larry

Andy, straightened out the pin order on the schematic symbol to match the .sub file, really thought I had it straight but they were off.? Guess that's what happens when you're doing several things at

Hello Andy , very intresting Idea .Indeed I will keep the decomp pin open. I am used to start with the netlist and generating a symbol automatickly. How do I involve the opamp2 symbol into the symbol

Also, there is this: If you can draw a schematic, then you can draw a symbol.? Don't be afraid to make a brand new symbol.? Taking the "easy way out" by only auto-generating symbols, demonstrates

Indeed, but I think it is a dangerous option, to be used only with great care. Parallel V sources can create infinite loop current, and non-physical transformers are not easy to detect, which being

Andy, your right thought I had those matching, will correct and give it a try. Larry

vOn Fri, Feb 21, 2025 at 09:35 AM, Carlo wrote: I do not think it was designed for that purpose. It does not eliminate the error message.? The error message comes about because of a topology check.?

Ahhh thank you guys for explaining the distinction. It seems obvious now the difference between the .sub and the .asy. I have re-uploaded my zip with the .asy.

Very good. By using Gmin stepping iteration, the spike is at 166 mA. Starting from 167 mA the heater resistance becomes negative and, as you highlighted, the Duncan Amps heater model begins to fail.