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phono cartridgeThe component in a phonograph turntable that holds the stylus, which is a needle attached to a cantilever arm. The vibrations of the stylus are transferred into electrical energy by a magnet inducing current into coils; one coil for the left side and one for the right. "Moving magnet" cartridges have the magnet attached to the end of the cantilever, while "moving coil" cartridges place two tiny coils on the end. In either case, the arm acts like a vibrating magnet.
Earlier phono cartridges were ceramic and used the piezoelectric effect to create the electrical signal. The cantilever end of the stylus arm actually contacted the ceramic base, which picked up the vibrations (see piezoelectric). See stylus.
Moving Magnet vs. Moving Coil Cartridges
Moving magnet (MM) cartridges employ a tiny magnet on the stylus armature that induces a current into two coils as the stylus moves in the groove. In a moving coil (MC) cartridge, the coils are attached to the moving armature and induce a current in the magnetic field. Hotly debated as to which method sounds better, high-end phono cartridges tend to be moving coil (MC).
|The Phono Cartridge|
|The cartridge is attached to the end of the tone arm on a phonograph turntable. A legacy system for sure, but there are thousands of people with huge vinyl record collections, and turntables and cartridges are still made.|
|Moving Magnet vs. Moving Coil|
|The advantage to the moving coil is less mass at the end of the cantilever because the coil is smaller than the magnet. There is also less electrical charge (capacitance). However, the moving coil voltage is also smaller and requires a phono preamp that steps up the voltage. See phono preamp.|
in low-frequency measurement technology, a component of moving-coil measuring systems that is used in light-beam oscillographs and moving-coil galvanometers. A moving coil is a light coil of wire that is located between the poles of a permanent magnet. In a galvanometer, the moving coil is suspended from very thin metallic ribbons; in an oscillograph, it consists of a very thin wire to which a small mirror is attached.
When a current flows through a moving coil, the coil is deflected in the magnetic field. In moving-coil galvanometers, the magnitude of the deflection is read by means of a microscope. In light-beam oscillographs, it is read on the basis of the deflection of a light beam reflected from the mirror.
REFERENCESSee references under STUB.
R. I. PERETS