Wednesday, 3 December 2014
Do you know what the 'lumpy' bit does...
its a Ferrite bead
We all have a basic idea about the purpose of each wire going in and out of our computer. But a few wires seem a bit off when it comes to their appearance. They have a cylindrical bead dangling near the end. So what’s this bead doing on that wire and what purpose does it serve? Today, we are going to unravel this mystery for you.
You will not only find this bead at end of charging cables but also mouse, keyboard and other peripheral cables. It turns out that lump’s called a ferrite bead or, more generically, a choke. It’s a fancy name for what’s basically an electromagnetic wave-bouncer. If you open this bead, you will not find any complex circuits but only a ferrite cylinder that is magnetic in nature. It is this magnetic quality of the bead that serves the purpose.
So basically, when current passes through any cable, it generates electromagnetic interference (EMI). Your electronic gadgets also produce EMI during operation. For example, if you connect a camera to your monitor, the camera would produce intereference and cause your monitor to flicker without the presence of a ferrite bead. If left unabated, EMI can wreck havoc with your computer peripherals.
These ferrite chokes ensure that signals are only sent in the intended directions and no EMI is transmitted between the peripherals. The choke dampens these EMI waves by acting as an EMI blocker. The blocking is most effective when it is near the source of the EMI, thats why you will only find these ferrite beads near the end of the cables. So, this little mystery is now solved! These tiny cyst-like beads make sure that our computer peripherals work properly and don’t cause any issues for the computer itself.
I hope that is clear...