For investigation of electric field patterns due to various electrode configurations and also permits easy demonstration of the related concepts to a group of students through overhead projector.
The apparatus comprises a clear plastic dish and a transparent rectangular base carrying a pair of 4mm socket terminals that can also hold adjustable electrodes.

Includes a set of 6 electrodes - two point source electrodes, two line source electrodes and two circular rings of 35 and 70mm diameter respectively.