Recording head

The recording head , also called speaking head SK, is a magnetic head designed as an electromagnetic transducer for storing sound signals in the magnetic layer of an audio tape .

In order to make acoustic signals storable, they first have to be converted into electrical signals. Such a conversion is done by a microphone . The electrical voltage emitted by the microphone is very small, so that it must first be electrically amplified before it can be fed to the recording head. The recording head consists of a magnetic toroidal core. Its most important parts are the magnetic core, the non-magnetic working gap and the coil. With the help of a head housing, they are combined to form a compact unit. The magnetic core consists of high quality, soft magnetic material, e.g. B. made of mu-metal or ferrite , with special requirements for high initial permeability , low coercive force , high saturation induction and high specific resistance . To reduce eddy current losses , the magnetic core is laminated or sintered ferrite is used. The magnetic resistance should be small, which amounts to a large iron cross section and a small iron path length. According to the defining equation of the magnetic field strength :

${\displaystyle \oint _{s}{\vec {H}}\ \mathrm {d} s=\sum _{n=1}^{N}I_{n}}$

generates an alternating current flowing through the recording head designed as a toroidal core :

${\displaystyle I=I_{0}\cdot \sin \left(\omega t\right)\;}$

a magnetic field proportional to the current.

The following mean:
H = field strength
I = current strength
Ω = angular frequency = 2 · π · f
t = time

See also

• Playback head | Erase head | Clock head | Tape head |