What is the importance of the little black bulb/cylinder at the end of a usb port cord? -

My ps2 eye toy cord broke. The part between the plug in and the black cylinder on the cord. What is the black cylinder?

That black cylinder is not a magnet, but is a cylinder of iron with a hollow center commonly called an iron core. This acts as an EMI (electro-magnetic interference) filter when a cable runs through it or is wrapped around it once or twice through the center. Some manufacturers use them, others don t. How it works: when electrical signals run through a wire they create small magnetic fields around the wire as the electricity moves through each wire that can create interference (noise) in neighboring wires and corrupt the data being transmitted. The iron core helps to absorb the magnetic fields and reduce the interference between wires thus helping create a cleaner data signal. Hope that helps.

From what I learned in college when coming to electronics, that lil black cylinder that you see there is a magnet. What happens is that with certain electronics, there needs to be a smooth flow of electricity. Usually electricity fluctuates up and down, and some electronic components cant handle more or less electricity than what they are rated for. So what happens is (u will find this in a lot of stereo amplifiers) that they will put a magnet somewhere along the wires and wrap the wires around it once or twice. That magnet some how smooths out the flow of electricity to the device so that it wont fluctuate up and down causing problems.

It s a EMI filter (electro-magnetic interference)