A Thermistor is a resistor whose resistance varies with it's temperature.
PTC means Positive Temperature Coefficient.
Which means that the resistance increase with temperature.
Thermistor heaters come in various forms from tiny to huge and are used instead of nichrome wire for all sorts of heating jobs such as hair driers
, bathroom fan heaters and in cars.
They have the advantage that they can be designed for specific temperature ranges and when they reach their maximum design temp they stay there as long as the volts are applied😊 Possible disadvantages for our purposes are the initial heat-up time and operating current. Current is typically high while heating up but falls dramatically when at operating temperature when the resistance is at maximum. I=V/R 😉. We'll see.
After reading that article I started trolling my usual suppliers for suitable versions
No luck yet, either too small or way too big ☹️
Anyway, I'm concentrating more on the alchemy side at the moment.
I have several commercial mini smokers, e.g. for HO/OO scale locos etc., to experiment with. So I'm attacking the problem of the elusive 'Black Smoke'.
As soon as I find some suitable thermistors heaters
I'll be off and running🤞
Cheers, Doug 😎