e. If the magnetic tape is passed across the gap (fig 1-11) oxide particles
in the tape will be magnetized in a pattern which is a function of the magnitude
and polarity of the original signal.
Understand that these particles do not
physically move, but are simply magnetized by the flux at the head gap so that each
individual particle contributes to an overall magnetic pattern.
Flux lines in a recording gap
Three tape heads may be used on the more expensive tape machines.
machines, such as those designed for home use, use the same head for record and
reproduce. It is possible to use the same head for erasing the tape; however, if
the same head is used for erasing as well as recording and reproducing, it will
require an additional run through of the tape.
Although one tape head can be used for three purposes of erasing, recording
and reproducing, there are some differences in construction of the heads.
basic construction of the heads (fig 1-11) is the same -- that is, the head
consists of a core of permeable material which is wound with a coil of wire. The
core material is usually of a laminated construction (as shown in (fig 1-12) rather
The nonlaminated heads are cheaper to contract, but they
usually produce poorer results.
The laminations, by reducing magnetic losses due
to eddy currents, produce a better response to higher frequencies.