Hi everyone!
I recently started experimenting with relays. I would like to give my relay a separate power supply so as to isolate Arduino from the relay.
I noticed though that my relay doesn't have a 3-pin jumper but only 2 pins (JD-VCC and VCC).
Can you tell me if it is possible to supply this type of relay with an external power supply? If yes, then on which pins should I put external power?
Thanks in advance!
I'd suggest you attach the external vcc to the vcc pin (the pin at the top where there is a cable attached already).
Just make sure you have the grounds connecting.
In other words:
external vcc goes to relay-board
external gnd goes to relay-board and Arduino power supply (both gnd are connected)
Arduino powered as before
If you want to power the relay board from a seperate supply, and also have opto isolation.
Remove jumper.
Connect relay supply to JD-VCC (not VCC) and relay ground.
Connect Arduino 5volt to VCC (on the row of pins).
Connect Arduino outputs to relay inputs.
DO_NOT_CONNECT Arduino ground to relay ground (doing so would defeat opto isolation).
Leo..
