The 4 and 5 pins are all single-pack relays, that is, there is only one coil and can only control one channel.

Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

The 5V relay is an automatic switch, which is often used in automatic control circuits, and uses a small current signal to control a large current. The input voltage range of the relay signal is 0 to 5V,

the current type and voltage level of the power supply should be Same as that of the control circuit.