Washington - The conundrum of the suddenly-useless-because-unmatched sock is a small but stubborn cultural meme. The digital era has its own less mysterious but more annoying version of such low-grade frustration: the purposeless connector or power cable from an obsolete electronic device.
Many people will have a drawer brimming with such coaxial vexations. And those who upgrade their iPhones have no choice but to add fistfuls of suddenly démodé “dock connectors” to the pile. Until recently I’d never thrown out such cables. The result: a decade-old pile of useless black and grey electrical spaghetti.
But recently, in a fit of decluttering, I disposed of nearly all these severed but lingering connections. I learned that decluttering can cause anxiety, as Oprah sagely cautions. She’s right that “letting go leaves space for more to come”. That’s just the kind of mental space I needed to contemplate the mystery e-mailed by Russell Yee, a seminary professor and author in Oakland, California.
Many cables, especially older ones, have a small cylinder on them. What does it do? First, four guesses, this time with a little help from Oprah:
a) “Own your power.” The cylinders are called accumulators – effectively they’re small batteries. They store a few milliseconds’ worth of power and keep data flowing through the cable even during minute fluctuations in electrical supply in the devices at either end.
b) “Everything and everybody is vibrating at different frequencies.” If only. The cylinders are designed to reduce the possibility of electrical interference with other electrical sources and devices.
c) “Real integrity is doing the right thing.” The cylinders ensure accuracy of data transmission by briefly delaying a portion. About 5 percent of the wires enter a coil in the cylinder, the rest go through; that path takes slightly longer, which makes it easier for the receiving device to check the data’s integrity.
d) “When I look into the future, it’s so bright it burns my eyes.” If one device has a power surge, the fuse-like technology in the cylinder prevents the surge from damaging whatever device is connected to it.
And the answer is… b). The cylinder is called a ferrite bead, ferrite core, or a choke. Cables can act like unintentional antennas, broadcasting electrical interference (“noise”) or picking it up. The task of a ferrite core is to prevent such interference.
The most common use of ferrite cores is to suppress noise emanating from the product through cords or cables. Ferrite cores can also reduce electrical interference to a cable, especially if it’s carrying data. The blender and electric can opener are virulent sources of interference, says John Drengenberg of Underwriters Laboratories, which develops safety standards, tests products and provides manufacturers with the UL safety mark. A ferrite core on data cables can “enhance the quality of your data stream”.
How does a ferrite core work? “Think of your cellphone not working well in a particular building,” Drengenberg. “The building is acting as a filter and reducing the signal from the cell tower while probably allowing AM radio signals, for example, to pass easily.”
The ferrite core acts as such a filter. – Slate /The Washington Post News Service