A study of the field around magnetic heads of finite length

This paper gives a determination of the field around magnetic heads of finite lengths and infinite permeability. The conventional Schwartz-Christoffel [3] transformation was used to map the inside of the polygon, corresponding to a finite magnetic head, into the upper half of the w plane. The mapping equation was derived and the equipotential lines, corresponding to a particular head-to-gap length ratio, were calculated. The equipotential lines for the same ratio were determined experimentally using the analog field plotter. A comparison of the two sets of curves shows that they are in fair agreement, the discrepancy being due to inaccuracy in the experimental measurements. Finally, the study includes a brief discussion of how the use of magnetic heads of finite lengths would increase the packing density of recorded pulses in both RZ and NRZ types of recording.