I have uploaded 2 files to the temp section that model a 120 degree
PTC thermistor, (the Epcos B59008C0120A040 from:
)
including the nonlinear behavior, modeled as 4 different temperature
coefficient resistors in series parallel.
The model is in file PTC1.asc
and the symbol is PTC_resistor.asy
The model also includes the internal temperature rise and thermal time
constant (which I guessed at, for lack of hard data). The symbol I
created for it has a third node that produces a voltage that
represents the internal temperature, with 1 volt = 1 degree C. The
curve across the resistor symbol indicates the 4 slopes in the model.
Everything I see this model doing looks pretty reasonable, but I would
appreciate anyone going over the whole thing and making suggestions
for improving it.
This was my first foray into model building with Spice.
