Static input variation

In power supply circuits and similar systems, this refers to the variation in output voltage when the input voltage is gradually changed within a specified range under rated load current conditions. It is one of the indicators showing the stability of a power supply circuit against input fluctuations, and the smaller the static input variation, the higher the stability against gradual input voltage fluctuations over a long period of time. It is useful, for example, in estimating the stability of the output voltage when the commercial power supply used as the input gradually fluctuates throughout the day due to the balance of supply and demand.