4 Channel Relay Board is a simple and convenient way to interface 4 relays for switching application in your project. Very compact design can fit in small area, manly this board is made for low voltage application. Features Input supply 12 VDC @ 170 mA Output four SPDT relay Relay specification  10A/24V DC Trigger level 2 ~ 5 VDC Header … Continue reading 4 Channel Compact Relay Board Using SMD Components ULN2003