Most of the AC power supplies on the market are AC constant voltage sources, in some specific test scenarios, such as for current sensors, current transformers, wiring harnesses, connectors, circuit breakers, low-voltage appliances and other products will need to use the AC constant current source, AC constant current source can be set according to the value of the current and the frequency of a certain voltage range within the output in order to verify the accuracy of the current or current-carrying capacity.