What Metal Is in a USB Cable?

By David Wenz

An "A" switch on a USB cable.
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USB cables connect many of our favorite devices to our computer, but most of us don't stop to think of what's going on under the hood -- or under the insulating sheath, more accurately.

The Cable

The top connector displayed here has a ferrite bead on it.
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There are a few basic parts to a USB cable -- there are the two connecting ends, and the wires inside, as well as the sheath around the wires. The cable allows transfer of data between the computer and the device attached by USB. Often, they have a ferrite bead on them that helps reduce some high-frequency "noise."

The Wires

The wires themselves are typically made of copper or silver, like many electronic devices. This is because both metals are particularly good conductors. If you cut open a USB cable, you would see the small wires inside, attaching to either end. These cables transmit data from point A to point B, passing the information along. Cables made with fiber optics -- ultra-fine optical glass that "beams" signals back and forth -- are starting to come onto the market as well.

Ferrite Bead

The bead in some cables is called a ferrite bead, and is used as an inhibitor of high-frequency interference, as all cables give off some radio waves by the nature of electromagneticism. As the name indicates, it contains ferrite -- an iron alloy commonly used in magnets. This can help prevent the USB cables from getting overloaded and ensure smooth operation by reducing ambient radio waves.


The connectors at either end of a USB cable are typically made of brass (a copper and zinc alloy) plated with nickel, though some are also gold plated. The "A" stream is the connector that plugs into the computer, while the "B" stream goes to the device. The connectors are often of different shapes in order for users not to get confused as to what end goes where.