University Physics
Electromagnetics Lab

Lab 1     Field Plots

In this lab conductive sheets of paper are used to measure voltage as a function of position. That is, the voltage field produced by various configurations of charged electrodes is measured.

Electrodes are drawn on conductive paper using conductive ink. A power supply is used to establish voltages between electrodes. Current flows through the conductive paper, setting up a voltage field between the electrodes. A voltmeter measures values of the voltage field at positions between electrodes.

Knowledge of the voltage field allows the electric field and the current field to be calculated.


Pre-drawn electrodes

Electrodes represent a coaxial cable

Electrodes represent a parallel plate capacitor

Plotting equipotential lines

Drawing electrodes

The line will dry in 3-5 minutes, but it will take 20 minutes to reach maximum conductivity.

Mount the conductive paper on the corkboard using stickpins at each corner.

Question to keep in mind

  1. What is your experimental error in each situation?
  2. What factors contribute to error?
  3. How do measurements compare with theoretical values?