An analytic expression for the x component of the field of a finite pole tip length magnetic head (thin film type) has been given by Potter [1]. Potter described the boundary potential extending beyond the pole tip edge with the expression

, where V
0is the pole tip potential. Computations based on conformal transformations of pole tips of semi-infinite height were the basis for Potter\´s selection of boundary potential. The slightly modified expression
![V(x, O) = V_{0}[C_{0} + C_{1}/(x + C_{2})]](/images/tex/9279.gif)
, as an approximation for the boundary potential beyond the tip edge, leads to expressions for the field components which agree well with those measured on a large scale model.

, and C
2were determined from a consideration of experimental field components for various experimental conditions and found to be a function of head geometry. The boundary potential used in these calculations has a slight discontinuity. This results from approximating the actual potential by a

function to simplify the problem. However, the purpose is to give analytical expressions for the field components agreeing with experimental measurements rather than to restrict the boundary potential to meet certain conditions as done by Potter.