Inrush current

At the startup of a power device, a larger than normal current flows due to charging current of internal capacitors. Due to transient phenomena, as the capacitors charge, the current decreases, and once fully charged, it stabilizes at a normal level. The maximum value of input current during the period from the startup of the power device until it stabilizes is called inrush current. Since inrush current can have adverse effects on power devices, many devices are equipped with safety features that limit input current at startup.