Lab 1     Field Plots

Lab 1 Exercise


Coaxial cable
Radius of the inner conductor = 1 cm
Radius of the outer conductor = 10 cm


Voltage measurements are taken along radial lines A, B, C, and D as a function of distance from the center.

Measured values of the voltage field in a coaxial cable are shown on the right.

The theoretical voltage values are,

where r is the distance from the center and VBB is the power supply voltage.

  1. How do measurements compare with theory?

  2. Plot the average measured value as a function of distance from the center. (Note that the measurements taken along radial line A appear to be off. Disregard the data taken along radial line A)

  3. Show error limits on your plot.

  4. What factors contribute to measurement errors?

  5. Draw field lines on the plot of constant potential lines shown in Figure 2. Construct the field lines so they and the constant potential lines form curvilinear squares.


    Figure 2