Interface design of humanity all interface can be connected directly leads to terminals very convenient is provided with 4 fixing bolt holes convenient installation use isolation optocoupler top quality strong anti-interference ability stable performance; trigger current of only 3mA. Products using LM2596S buck chip a slight fever which is a normal phenomenon relay long time work has fever normal are a normal phenomenon; Module application: 1 12V relay contact capacity of 10A 250V with optocoupler protection. Onboard power supply module does not need an external power supply. I/O export driven active low. 2 Can be used as MCU development board module can be used as electric control can also be used as a PLC extension output.