Check the listing for details. Relay Module Interface Boards for Arduino Low Level Trigger 1/2/4/6/8 Channels. Condition: New. Listed at 2.06 USD. Features Using high-current relay , AC250V 10A DC30V 10A Contact some independent wiring , safe and reliable Standard interface , can be extended in a variety of development board With fixed screw holes for easy installation Suitable for a variety of platforms such as 51/AVR/AVR/ARM Module Description : 1 , the module complies with international safety standards , the load control area and regional isolation tank ; 2, using double-sided FR-4 circuit board design, high-end chip production process ; 3, using loose music authentic relay control ; 4, with the relay instructions , pull off, disconnect does not shine ; 5, the signal input has a low signal , often beginning with a common terminal will be turned on ; 6 , the relay can control the various devices and the load ; 7 , 8 and 8 normally open normally closed contact ; 8 , blue KF301 terminals to the control line is more convenient. 9 , Module size : 138m * 56mm * 18.5mm ( L * W * H ) , Weight : 120g 10 with 4 fixing bolt holes , hole 3.1mm, pitch 131mm * 49.5mm 11 , finished by 100% functional testing and stability testing Two module interface : 1, VCC: 5V power supply connected to the positive 2, GND: 5V power supply connected to the negative 3, IN1-IN8: trigger signal , active low Relay outputs : a 12- line interface, the interface can be directly connected to all leads , user-friendly 1, NO1 - NO8: normally open relay interfaces , relay before the vacant after the pull shorted with COM 2, COM1 - COM8 Relay Common Interface 3, NC1 - NC8: normally closed relay interface relay shorted with COM ago , after the pull- vacant Wiring: VCC: positive power supply system GND: System power negative IN1 - IN2: relay control ports 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: 1, support all MCU control. 2, the industrial sector; 3, PLC control; 4, smart home control 8 channel relay module