Pickup cartridge, moving-magnet  --  The stylus cantilever is joined to the free end of a lightweight cylindrical magnet made of material such as samarium cobalt. It is pivoted at the far end, and surrounded by four yoke pieces spaced at 90 degree intervals. Each opposite pair of yokes forms a magnetic circuit through one of two coils. Movement of the magnet in one direction induces a field in the appropriate pair of yokes and from there to the coil.