In a magnetic recorder, the generally ring-shaped electromagnet across which the tape is drawn. Depending on its function, it either erases a previous recoding, converts an electrical signal to a corresponding magnetic pattern and records it on the tape, or picks up a magnetic pattern already on the tape and converts it to an electrical playback signal.

2-Head: The system used on most cassette recorders, requiring that playback occur after the recording has been made. 3-Head: Refers to the recording/playback head configuration within the recorder. A 3-head system allows simultaneous playback of recorded material.