The tape head consists
of a ring of soft
magnetic material,
called the core, with a
small gap in it.
A coil is wound around
the core.
The tape travels over
the gap in the core.
During recording, an
audio signal causes
current to flow through
the coil producing a
magnetic field in the
gap, as shown by the
blue lines of force in
the diagram.
As the audio signal
varies in amplitude and
frequency so does the
magnetic field.
The tape consists of a
plastic film coated with
a material that is
magnetised by the field
as it passes over the
gap.
As the magnetic field
varies in strength so
does the magnetism
stored on the tape.
During playback the tape
passes over the same
head. (it is called the
record/playback head).
This time the magnetism
stored on the tape
induces a voltage in the
head coil.
This voltage is
amplified and used to
drive a loudspeaker.
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