USB Power Supply Switch via Relay

Thread Starter


Joined Jun 30, 2019

my question is a simple one, please don't laugh. :)

I want to power on and off a USB device via a relay. I already programmed it. My question is pretty basic:
I need to connect the red cable (+5V) to the relay to on and off the device, but do I also need to connect the black cable (ground) to the relay, or can I just connect the ground cables directly?



Joined Jul 18, 2013
Are you using a signal from the USB to switch the coil, or using the 5v+?
If so, how do you intend to switch the coil, or are you referring to the relay contacts?
A little more explicit would help.


Joined Apr 11, 2010
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