An inductance coil is a wire wound round and round on an insulating tube that is insulated from each other, and the insulating tube may be hollow, or may contain an iron core or a magnetic powder core, referred to as an inductor. In l, the units are Henry (h), Millihenry (MH), Micro Henry (uh), 1h=10^3mh=10^6uh.
Repair of medium woofer: most of the speaker voice coil skeletons are made of aluminum alloy foil. First, heat the voice coil with a hair dryer until the glue softens.Then, use a surgical blade to separate the voice coil from the paper basin along the outer edge of the voice coil.
When the current I passes through the voice coil in the magnetic gap with the magnetic field intensity B of the speaker, the voice coil will receive an electrical force F=BLI(L is the length of the voice coil), and the force direction shall be according to the left-hand rule. Here voice coil is not only one of the factors of the force, but also the recipient of the force, but also plays a considerable role in the size of the force.