Relay board is one kind of very popular switch module. You can use it control any devices on or off. This is a DC 12V controlled 4 channels relay module. It has high level trigger. Trigger current needs not less than 5mA, it can be used in many industrial systems that use DC 12V power supply.
- 4-Channel Relay interface board, - Each one needs 15-20mA Driver Current - Equipped with high-current relay: DC30V 10A AC250V 10A