Hey guys!

I think the ceramic cartridge heaters that are being used in place of resistors for hotends are pretty neat. I just want to try and understand them a little more and haven't been able to find info or datasheets on them.

I have a question about their operation. From what I gather from a few web searches, it seems like they are ran at 12V and the temperature is controlled by changing PWM values which increase the percentage of current it receives and using a thermistor to regulate the PWM to maintain temperature.

What happens if you run it at 12VDC and dial the current to a certain value with a potentiometer to set the heater cartridge at a fixed temperature?

Why we would prefer to depend on a thermistor to regulate the temperature instead of setting it to a fixed current and temperature?