Procedure:

Fasten a sheet of paper, preferably graph paper, to the field mapping board, and trace the chosen electrode shapes on the paper using the plastic template which matches the electrode template.

Before turning on the power supply, connect the voltage reading electrode of the voltmeter to the U shaped probe and connect the common electrode of the voltmeter with the negative or grounded terminal of the power supply. After making these connections, turn on the power supply to a reasonable potential difference, approximately 10 Volts. Move the U shaped probe along the paper where the potential measured by the voltmeter is constant, marking the paper as you go. Make a line through the points and record the potential of this equipotential line. Repeat for different potentials until a reasonably complete picture of the nature of the equipotential surfaces (lines) emerges.

The lines of Electric force are everywhere perpendicular to these equipotential lines. Draw in these so called electric field lines for each template. Use the equipotential surfaces to develop a reasonably complete picture of the electric field in between the conductors. Do this for 2 templates. For each picture thus obtained, do the following:

1. Point out, qualitatively, where the electric field is strong and where it is weak, and what it is about the field lines which indicates this.
2. Compute field strengths for a few points between the conductors. Indicate the magnitude and direction of the electric field.