Cassette tape
The Compact Cassette, also commonly called a cassette tape, audio cassette, or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. Invented by Lou Ottens and his team at the Dutch company Philips, the Compact Cassette was released in August 1963.[2] Compact Cassettes come in two forms, either containing content as a prerecorded cassette (Musicassette), or as a fully recordable "blank" cassette. Both forms have two sides and are reversible by the user.[3] Although other tape cassette formats have also existed—for example the Microcassette—the generic term cassette tape is normally used to refer to the Compact Cassette because of its ubiquity.[4]
For other formats, see List of magnetic tape cartridges and cassettes.Media type
Analog signal, in four tracks
Most commonly 30, 45, and 60 minutes per side (C60, C90, and C120)[1]
Tape head
Audio and data storage (replaced by CD)
August 1963
Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film (magnetic tape) is passed and wound[5]—essentially miniaturizing reel-to-reel audio tape and enclosing it, with its reels, in a small case (cartridge)—hence "cassette".[6] These spools and their attendant parts are held inside a protective plastic shell which is 4 by 2.5 by 0.5 inches (10.2 cm × 6.35 cm × 1.27 cm) at its largest dimensions. The tape itself is commonly referred to as "eighth-inch" tape, supposedly 1⁄8 inch (0.125 in; 3.17 mm) wide, but actually slightly larger, at 0.15 inches (3.81 mm).[7] Two stereo pairs of tracks (four total) or two monaural audio tracks are available on the tape; one stereo pair or one monophonic track is played or recorded when the tape is moving in one direction and the second (pair) when moving in the other direction. This reversal is achieved either by manually flipping the cassette when the tape comes to an end, or by the reversal of tape movement, known as "auto-reverse", when the mechanism detects that the tape has ended.[8]