Control and protection switching device circuit with self-tuning function

The utility model discloses a control and protection switch electric appliance circuit with a self-tuning function, which is characterized by comprising a self-tuning key circuit, a three-phase current sampling circuit and a microprocessor control circuit, the microprocessor control circuit comprises a microprocessor, the self-tuning key circuit comprises a sixth key switch, and the sixth key switch comprises a fourth key switch. One end of the sixth key switch is grounded, and the other end is connected with the I/O pin of the microprocessor. According to the circuit, a user only needs to carry out self-tuning on a product through the sixth key according to the actual running current of the load of the control and protection switching device, the mode is simple in operation and accurate in setting, when the microprocessor detects that the sixth key is pressed down, the internal microprocessor judges whether the key is pressed down through software, and if the key is pressed down, the user can carry out self-