Inrush current refers to the peak current flowing into the power supply equipment at the moment the power is turned on.

This peak current is much greater than the steady-state input current due to the rapid charging of the input filter capacitor. The power supply should limit the surge level that AC switches, bridge rectifiers, fuses, EMI filter components can withstand. Switching the loop repeatedly, the AC input voltage should not damage the power supply or cause the fuse to blow.

Inrush current also refers to the non-repetitive m ximum forward overload current that causes the junction temperature to exceed the rated junction temperature due to abnormal conditions in the circuit.