Current amplifier which thermally stabilizes electrical devices is a kind of current source for testing use. For example, it can be used as low-voltage super-current source in motion stability test and temperature rising test of air circuit breaker, contactor, relay, and bus-bar. In addition, it can also be used as check current source of current transformer. Current amplifier, no matter if it’s the single phase or the three phase, the AC current or the DC current, is consisted of super-current generator (transformer), regulator and controller.