Consumer Electronics

TAPES

Modern magnetic tapes consist of a non-magnetic base (paper, cellulose acetate or p.v.c. for example) coated with a magnetic material. The base obviously needs to have strength and suppleness. The magnetic material (often red or black iron oxides) is a very finely divided powder mixed in some binding substance (lacquer, for instance), and the coating applied to the base material has to be very smooth.

Unevenness in the surface of the tape will tend to cause broken contact with the heads and consequently an undulating level of recording. The magnetic material needs a high coercivity to prevent, in particular, very large demagnetisation losses at treble frequencies, and a high remanence to give a good level of recording.

Tapes are usually ...