O'Reilly logo

Sound Engineer's Pocket Book, 2nd Edition by Michael Talbot-Smith

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

16  Analogue Recording and Reproduction

Formulae

Magnetomotive force, m.m.f is given by

m.m.f. = NI

where N is the number of coil turns and I is the current.

The units of m.m.f are ampere turns/meter (At/m)

The intensity or field strength is the total force acting per unit length I of the magnetic circuit. It is called the magnetizing force H.

H = m.m.f./l = NI/l(AT/m)

The magnetizing force causes a flux Ф in the magnetic circuit.

The flux density B is the flux per unit area. The unit is the tesla (= webers/m2).

Ф = m.m.f./S

where S is the reluctance of the circuit.

Figure 73 shows a typical BH loop (hysteresis loop).

image

Figure 73  Hysteresis loop ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required