The mechanism that reads and writes magnetic tape as it moves past. Quality tape recorders have three heads: play (read), record (write) and erase. Many consumer products have only two: one that plays and records and another that erases. Machines that record audio for movie film may have a fourth head that writes an inaudible synchronization signal. See magnetic tape
A Two-Head Tape Recorder
This machine has one head for reading and writing (playing and recording) and another for erasing. When in record mode, the tape passes the erase head first.