Problem with Relay Module

I’m not sure whether I’ve wired this up wrong or if I have a defective board.

I’ve connected VCC to +5v on Arduino, GND to GND on Arduino, and the K1 (control for 1st relay) to pin 13, and have that cycling between high and low every second, but I don’t hear any clicking.

I’ve also tried testing it out with another 9v circuit, and for some reason the ground on the terminal blocks seems to be connected to GND on the Arduino(!), although again I might just be doing it on.

Also, could someone please explain what NO, COM and NC means on the terminal blocks? Thanks.

NO = Normally Open. Connected to COM when the relay activates. COM = Common. NC = Normally Closed. Connected to COM until the relay activates.

Thanks for the info.

So should if I want to control a light, should I connect ground to GND on the relay, and live to NC? But then what about COM?

And should this kind of relay click when activated, and if so do you think the board is defective?

alfo: Thanks for the info.

So should if I want to control a light, should I connect ground to GND on the relay, and live to NC? But then what about COM?

And should this kind of relay click when activated, and if so do you think the board is defective?

To use the relay as a switch, use COM and NO as the two terminals of the switch. For a lamp you would typically put the switch in the Hot side of the circuit. Connect Hot to COM, NO to lamp, and lamp to Neutural.