Many people have this small cylinder on their laptop charger, yet no one has really investigated or asked what it is.
It turns out the little cylinder part on the laptop charger is called a ferrite bead. It’s extremely important in keeping your laptop running.
All of the small parts inside your laptop run because of radio frequencies. Your casing that holds everything together, stops them from interfering with each other.
The charging cable attached to your laptop acts as antennae, broadcasting your laptop’s vibrations as radio frequencies and picking up signals which creates interference. So the cylinder, or ferrite bead, prevents interference between your electronic devices.
Not something everyone needs to know or understand, but at least now if someone asks you know the answer!