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Volts from an USB cable Answered

I need to know how many volts a usb cable provides from a laptop. I couldnt find any information on google and I know that someone here has to know.


thats only if the chip you power requests power from the port through the data cables. otherwise, you only get 100 ma

The two main voltages in a computer are 12V and 5V. In the case of a USB port it is 5V. Perfect for most projects.

hang on a sec. dont start yet because: unrequested, you can only get 100ma from a usb port. requested, you can get 500ma. exceed the limits, and either the main board fries or the port gets shutdown. also, you will find a bare wire (sheild) and a string (feed cord)

its like this...

Inside a USB cable.JPG

not all cables are shielded... Which is handy for dumb projects, any constant data stream ones and the like of camera ones tend to be though.

The red and black wires are a 5 volt line, the other two are data cables, red - positive, black - negative, green - data, I cant remember the other colour It might be blue, it's data aswell.

it also depends on the cable, standard, yes, but really cheap ones don't follow any code.

Thanks, I posted this and within 10 minutes there was an answer. Now wish me luck I don't blow up my house :P