1. Field of the Invention
The invention relates to a magnetic head intended particularly to be part of a recording device with a multiplicity of heads.
2. Description of the Prior Art
A magnetic head is a device for recording and/or reading data on a magnetic support. Recording is achieved by causing the magnetization of the support to vary locally.
Such a head comprises two magnetic poles separated by a nonmagnetic gap. To record data, a magnetic field is induced in a magnetic circuit comprising the two poles and the magnetic support is applied against the ends of the poles and against the gap. Thus, the magnetic circuit is closed by the support at right angles to the gap, which makes possible magnetization (or demagnetization) of the support at this spot.
Reading of data recorded on the support is obtained by an electrical signal which results from an electromotive force induced by varying the magnetic flux in the magnetic circuit closed by the support. This variation of flux comes from the variation of the magnetization on the support when the latter is moved relative to the head or vice versa, when the head is moved relative to the support.
For some applications it is considered that a signal is recorded on the magnetic support only when the magnetization of this support exceeds a determined threshold. The magnetizations of the support below the threshold, during reading, cause parasitic signals which it is preferable to eliminate by special arrangements of the reading circuit.
The magnetic head according to the invention makes it possible to magnetize the support only when the magnetic flux exceeds a determined threshold, which eliminates the parasites during reading.