Caption

Scanning electron micrograph (SEM) of the surface of a long-playing record (L.P.), showing a spherical diamond stylus sitting in one of the concentric grooves. The L.P. is made by pressing the recording information onto a softened (heated) PVC disc. The stylus sits nicely in the V-shaped groove, and lateral vibrations are picked up by the stylus as the record rotates: these are transduced by a moving-coil or moving- magnet cartridge into an electrical signal, which passes through an amplifier to be heard on loudspeakers. Magnification: X 250 at 35mm size, X 1760 at 8x10-inch size.