In inverter welding machines, the core function of a PTC thermistor is to act as an inrush current suppressor. Connected in series in the welding machine's power input circuit (before the rectifier bridge), it protects key components such as the rectifier bridge, filter electrolytic capacitors, and switching transistors (MOSFET/IGBT) from being damaged by the huge inrush current generated by capacitor charging during startup.

In inverter welding machines, the core function of a PTC thermistor is to act as an inrush current suppressor. Connected in series in the welding machine's power input circuit (before the rectifier bridge), it protects key components such as the rectifier bridge, filter electrolytic capacitors, and switching transistors (MOSFET/IGBT) from being damaged by the huge inrush current generated by capacitor charging during startup.