The electric potential in the neighbourhood of a thin slit

When a slit opening is made in a plane electrode forming the boundary between two unequal electric fields, a distortion of the fields occurs. This paper studies the influence of the slit opening on the electrical potential distribution on both sides of the slit. A theory is developed for calculating the potential at any point, and from it two methods are derived for finding curves of equal potential disturbance. Several computed curves are presented for each method. The curves suggest a simple graphical construction for approximating the potential disturbance at points not too near the slit. Because the potential disturbance is the same at image points on either side of the slit, it is found that all the important formulas can be expressed in terms of distances, without regard to sign. To facilitate the reproduction or extension of this work, a computer program in the widely used Fortran language is given for the simpler of the two methods.