what's the point of the little plastic cylinder on the end of my laptop power cable?

[dpopiz]

the power cable on my laptop was getting really hot and not giving it power, so I unplugged it and chopped it where it was getting hot. sure enough, it was all burned up inside. but a new power brick is $30, and the brick is fine, so I want to fix it myself.

my question regards this:
there's a little plastic cylinder near the end of the cable with the connector (lots of different kinds of cables seem to have these). so what does it do? do I need it? is it a filter of some kind or just and enclosure for a solder point?

 

[sswingle]

Its a ferrite cylinder that the wire wraps around. You can usually open it up, you can see the wire just loops around it once and goes along its merry way. It's supposed to keep interference down.

 

[dpopiz]

so would it hurt if I just left it out when I solder the connector back on? (it would be virutally impossible to keep the cylinder)

 

[Brian23]

it should be alright without the ferrite cylinder on there, but if you have any weird problems after you re-solder it, there are snap-on ferrite cylinders you can buy. (Radio shack?)

 

[Mday]

its a ferrite choke, it helps prevent EMI.