4-channel relay expansion board Can control a variety of household appliances, and high-current loads Adopt high current relay, AC250V 10A DC30V 10A. Contact part of the independent wiring, safe and reliable Standard interface, can be expanded in a variety of development boards With fixing screw holes, easy to install Applicable to 51/AVR/AVR/ARM and other platforms 4-channel relay output module, relay output contact 250A 10A. input IN1, IN2, IN3, IN4 signal line low level effective. vcc, GND power input, can relay separate power supply relay power input JD-VCC.