Common ground issue...

Hi there. I tried to search the forum, but couldn’t really find anything about it.

I have recently dusted off my old Arduino NG. I Have created a cooling controller for a small server rack. It’s constructed with a resistor (receiving a PWM signal) to control the fans.

Worked fine with my small test fan (powered from the arduino), but i want to connect 4 high-power ones for final install. I fed the transistor/fan power from my bench-supply, and the arduino still from the USB cable.

I know the arduino and the benchsupply need common ground. But how do i do that exactly? Do you just connect one of the Gnd pins on the arduino to the “-” on the power supply?

Im sorry if this have already been answered before…

Hi griffer,

There is a nice short article by Mike Cook, who is member of this forum http://www.thebox.myzen.co.uk/Tutorial/Power_Supplies.html I think it explains everything in great details.

Do you just connect one of the Gnd pins on the arduino to the "-" on the power supply?

Yes, that is how to do it.

Lefty

Ahh great thanks guys :).