When an electrical equipment/device is firstly powered up, the inrush current will be drawn; at this moment, the power supply will lower the output voltage to offer a higher current. Hence, it is necessary to choose an appropriate power supply for the equipment by considering and evaluating the equipment’s tolerance to the voltage drop. Having the electrical equipment turned on repeatedly or put under the overload condition for a long period of time might shorten the lifetime of the power supply or lead the power supply to malfunction.