On Fri, Feb 21, 2025 at 06:01 AM, Andy I wrote:
The spike around 160 mA is the "singularity" I mentioned earlier.
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This shows how the Duncan Amps heater model fails, when the heater's temperature becomes too great.? The resistance hits the singularity, then goes negative, causing the heater to generate energy instead of dissipating it.
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.
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By the way, you can eliminate that error message, by adding a 1T resistor across the heater. ?That stops LTspice from thinking the nodes are floating.
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BTW, on LTspice Control Panel->Hacks! tab there is a checkbox named "Add GMIN across current sources".?Is it supposed to "address" such a problem/error related to the current source's infinite impedance ?
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Carlo