Input noise immunity

This is one of the values that indicates the performance of a power supply device. It represents the maximum level of noise, such as that included in the input voltage, that the power supply device can withstand while maintaining normal operation. A pulse voltage simulating noise is superimposed on the commercial power supply and applied to the input terminal of the power supply device. As the pulse voltage is increased, the maximum pulse voltage at which normal operation can be maintained is measured. The higher this value, the greater the device's resistance to noise contained in the input.