Zener diodes and PTC thermistors for circuit protection

Thread Starter


Joined Aug 5, 2014
Hi, I joined the forum so I could ask this. I'm adding some basic circuit protection - overcurrent, overvoltage and reverse voltage protection. I'm doing this by a PTC thermistor to prevent overcurrent, a MOSFET to prevent reverse voltage and a zener diode to clamp any overvoltages.

I haven't encountered this approach, at least not this combination, in any research so far. I was wondering if anyone could tell me if there are any reasons why not to do this? The MOSFET for reverse voltage protection seems pretty straightforward, but as long as the components are carefully selected the PTC thermistor shouldn't 'clash' with the zener diode in any way, should it?