Relay Energizes on Ground (0V) Signal and general dimensionsBy
4 Stars for: lack of documentation, general OK build quality, and good price. Would Buy Again. Good product for quick deployment to switch a simple load on/off with a PIC micro-controller. Note that a 0V / GND Signal into any input on the relay board will energize / activate the relay, while a 5V signal will de-energize the relay. Relays listed for 30VDC / 125-250VAC both at 10A, but id never trust something with tiny screw terminals to that extent. There is a set of "VCC / GND" Jumpers on the board. I believe this is used to bridge the circuit from the optocoupler output stage to the to use the optocoupler input voltage. You could probably remove this jumper if you want to isolate the power supplies, but I did not test this. Moving the jumper over 1 position just shorts out the board ;). Lastly, attached some general dimensions of the unit if you're building an enclosure or mount for it.