It has the same function as an ordinary transformer, but for the convenience of assembly, the lead wires are replaced with hard wires and directly plugged and soldered on the circuit board. The specific function is to convert the 220v voltage into low-voltage alternating current, and cooperate with the rectifier, filter and voltage stabilizing circuit to provide power for the whole machine.

The unused pins can be cut off. If they are soldered on the board, the connections should be disconnected.