Magnetic field by that loop. Ampère's law is always valid for steady currents and can be used to calculate the -field for certain highly symmetric situations such as an infinite wire or an infinite solenoid. In a modified form that accounts for time varying electric fields, Ampère's law is one of four Maxwell's equations that describe electricity and magnetism. A charged particle moving in a -field experiences a "sideways" force that is proportional to the strength of the magnetic field, the component of the velocity that is perpendicular to the magnetic field and the charge of the particle. This force is known
Tweeter These designs operate by applying current from the output of an amplifier circuit to a coil of wire called a voice coil. The voice coil produces a varying magnetic field, which works against the fixed magnetic field of a magnet around which the cylindrical voice coil is suspended, forcing the voice coil and the diaphragm attached to it to move. This mechanical movement resembles the waveform of the electronic signal supplied from the amplifier's output to the voice coil. Since the coil is attached to a diaphragm, the vibratory motion of the voice coil transmits to the diaphragm; the diaphragm