self-regulated PTC heater


Thread Starter


Hi all,

I have a PTC heater that's self-regulated at 60C, rated at DC 24V20W. However this is still too hot for me, can I regulate it further? The ideal temperature would be around 40C.

I'm thinking about using PWM via MOSFET, and adjust the duty-cycle. But I'm not sure if the high frequency power cycle might harm the PTC.

Another option would be using a relay with a thermosensor, limiting the temperature in a window(say, 37C to 40C). But there could be delay between the PTC and sensor, and I would much prefer a more precise control(say, under 1C).

Anyway, any ideas?
PWM won't do any harm - your problem will be monitoring the temperature (feedback) in order to regulate it accurately as it will vary with ambient/contact with other items etc.
Thanks! sure I will monitor it, but it's a one-time thing I guess? Once the calibration is done, it will remain the temperature if I don't change the contact and ambient.

BTW, I'm also consider using the same method to control the speed of a 3-pin cpu fan. Some people told me the PWM signal will interfere with the intenal clock of the fan, and it won't work at all. Do you think it's doable?