Have you ever wondered what that little cylinder-shaped lump phone on many power cords, monitor cables, and other such devices is for? Is it just there to make us wonder what its for? Actually, it turns out that it does in fact serve a very real purpose.
Giz helps dispel any mystery that might have surrounded the little cyst-like contraption coming out of cords. If you were to open one up, what would you expect to find? If you were thinking some kind of small circuit board or transformer, you would be completely off.
The cylinders are actually known as ferrite beads or a choke, and is used as an electromagnetic wave-bouncer. Without the ferrite it is possible that many of our devices would cause signal interface with each other and other distortion that the choke prevents, such as screen flicker, a buzzing noise in your speakers, or even in extreme cases it could mess with components in your PC hardware.
So there is no longer a need to wonder if the cord lumps service a purpose or not. Although not exactly attractive looking, its good to know that they are what is protecting our devices from having electromagnetic interface that gets in the way.