I am kind of dipping my toe in this lake. Not a hardware/electronics person, more of a software guy (programmer). I am not able to easily find information about the 12V 4 Channel Relay (duinotech).
where would one plug the hot wire (main) and what are the other 2 why are there 2 GND pins and why is there a jumper connecting the COM to one of the GND pins.
Please point me in the direction that makes it easier for me to get this information.
Here is an image of the relay module that I actually have (notice how the relays themselves blue have different text on them from the previous image. Can someone explain how come this does not mention a 30VDC rating and has a duplicate line?