4-channel relay control board module with optocoupler, 4 way relay module for arduino 4-channel relay output modules, relay output contacts 250A 10A. Input IN1, IN2, IN3, IN4, the signal line LOW effective. VCC, GND power input, can relay a separate power supply relay power input of JD-VCC. Uses: support all MCU control. the industrial sector PLC control smart home control Module parameters: Size: 75mm (length) x 55mm (W) x 19.3mm (height); Weight: 58g; PCB Color: Blue; board four weeks with four screw holes, Read more about 4-channel relay control board module with optocoupler, 4 way relay module for arduino[…]