Re: USB port voltage
We use the usb port to charge a lot of our devices na... could someone tell me what is the exact output voltage of the usb port..?
While Wikipedia and other reference sources are valuable, in some cases, the sheer amount of information may be overwhelming. Here's a condensed answer to your question:
The short answer is 5V. The two outer pins of the common USB port supplies the +ve and -ve 5V terminals. The two inner pins are the data lines.
A slight expansion: The current that can be drawn from a normal USB port is limited. If a connected device tries to draw too much current, the output voltage automatically drops. This prevents overloading and short-circuits. This is one reason why some USB devices like external hard disks do not function reliably with some computers.
As with many technical standards, there are variations and sub-types.