Low Cost Reverse Polarity And Over Current Protection (corrected) Guide

A thermistor is placed in series with the input. Normal Operation: The PTC has very low resistance.

The Gate-Source voltage becomes positive (or zero), keeping the MOSFET closed and blocking current. 2. Over-Current Protection A thermistor is placed in series with the input

Unlike a standard diode that loses ~0.7V, a (e.g., AO3401 or IRF9540) has very low "on-resistance" (RDSon). A thermistor is placed in series with the input