Audio tape recorders are fairly common these days. Most of them operate in a similar way. They have two reels-a full supply reel of magnetic tape and an empty take-up reel. One end of the tape from the supply reel is attached to the take-up reel. Between the two reels, soft rubber pinch roller presses the tape tightly against a metal rod called a capstan. When the tape recorder is switched on, a motor turns the capstan. As the capstan turns, it pulls the tape from the supply reel. At the same time, the take up reel pulls gently on the tape to wind it up.

Before the tape reaches the capstan, it passes the heads of the cassette. The ones you use at home are cassette recorders. Open-reel tape recorders are used by recording studios and broadcasting stations.

NOTE: The Japanese firm of Sony tried to make a miniature version of their cassette recorder and ended up inventing the ‘Walkman’!