How does the USB power wire work?

I stripped a USB cable. The cable itself has four wires: white, black, red, and green. Each USB cable has two ends, each with a connector. One one end is a type-A connector, and on the other a micro-B connector. The type-A connector has four pins, and the type-B has five!

What are the four wires? The four colors correspond to four names. The black and red are power wires, and the white and green are data wires. Black is “GND” or ground. The red is “VBUS”, or +5 volts. The white is “D-” and the green is “D+”, where “D” stands for data.

Each pin on the connector is connected to one of the four wires. On the type-A connector:

   |                            |
   | +========================+ |
   | |   ___            ___   | |
   +-|  [___]          [___]  |-+
     |                        |
     |  |GND|  D+  D-  |+5V|  |

Ignoring the data pins, you can just use USB to power things. I made a USB LED light by connecting:

I just released Vidrio, a free app for macOS and Windows to make your screen-sharing awesomely holographic. Vidrio shows your webcam video on your screen, just like a mirror. Then you just share or record your screen with Zoom, QuickTime, or any other app. Vidrio makes your presentations effortlessly engaging, showing your gestures, gazes, and expressions. #1 on Product Hunt. Available for macOS and Windows.

With Vidrio

With generic competitor

More by Jim

Tagged . All content copyright James Fisher 2017. This post is not associated with my employer. Found an error? Edit this page.