Measure USB voltage

RAA · May 10, 2007

Is there a way to measure what voltage a port has? I have a multimeter. And I'd also like to test a cable that goes into a USB port to make sure the cable is not somehow loosing voltage. Can i just ground the multimeter and carefully measure a pin or strip at the end of the cable that goes into a device? The cable in question has 4 wire strips.

Spion · May 10, 2007

http://pinouts.ru/Slots/USB_pinout.shtml

that should answer your question

FireMogle · May 10, 2007

I am not 100% but you should be able to test the 5+ and the ground and see what voltage is being outputed.

RAA · May 10, 2007

Spion said:
http://pinouts.ru/Slots/USB_pinout.shtml

that should answer your question

Yep, exactly what I needed thanks. The 5V reads exactly 5.00V and the other 3 strips read -0.01, 0.01 and 0.01. Seems that my mobo is still giving correct USB voltages. I used one of my PSU molex connections for ground.

Adragontattoo · May 10, 2007

USB is always 5v.

There is supposedly a very similar connection tha does 12v but I have only read about it and have never seen it released.

RAA · May 10, 2007

Yes well I'm having issues with a device and so I wanted to rule out my mobo being the problem, i.e. over or under volting USB 5V. No problem, my PC is not to blame and I can now point my finger else where.

freakdiablo · May 10, 2007

Sounds right, 5v 1/2 amp (i think). What problem are you having with the device? might be able to help on that end.

RAA · May 10, 2007

It's a USB powered circuit board. I think it must be a fault with the board. I have already gone through one of these boards so I thought that maybe my PC was damaging them but that is obvioulsy not the case.

Measure USB voltage

RAA

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