Magnetic Field Mapping



First portion of the lab is slow decay. Pre wire boards to place switch in line with DC voltage from 550. Voltage probe measures voltage drop across cap/resistor to ground when switch is opened. Resistor is wired parallel to cap. Attach DC voltage and voltage probe across cap and resistor network.

      Second part is fast decay, 550 supplies an AC voltage. Use voltage probe to monitor decay across cap. Switch is either closed or can be bypassed entirely. This portion uses caps in series and parallel. Students will re wire in this portion and become confused. Re wiring by you or TA is common for this lab. Refer to schematics in lab manual.


  • Solenoid F4
  • Helmholtz Coil pair F4
  • Axial Field Probe F1
  • 10Ώ Resistor, block mounted F1
  • Function Generator, TEK 250 G3
  • Oscilloscope TEK 2215 H3
  • 30 cm ruler I4
  • Triangle I6
  • Meter stick* (double stick tape to bench) I2
  • Tripod Stand (w/ 2 base feet on same side marked at tangent to foot) J5
  • Rod clamp K4
  • 3 prong clamp (swivel type) K4
  • Al, Rod 6-9” M9
  • 2 BNC cable, 3 ft & 2 ft lengths end of FF
  • BNC/DBL male adapter
  • Leads 218
  • Double stick tape, narrow 218 workbench



Using banana plug cords, connect oscilloscope to the probe coil (represented as pick-up coil in diagram below).

Next, link the function generator to the Helmholtz coil and a 10 Ohm resistor in series.

Refer to diagram below for setup:


Special instructions on Construction and Wiring of Helmholtz pairs:

1. Coils starts at inner radius from Red contact post, winds outward towards Black

contact post.

2. Series Wiring : Power supply + and – both to Red posts, Black wired to Black.

3. Values of parameters: N 1 =N 2 , R 1 = R 2 , B 1 = B 2

4. The 10ohm resistor should be placed in series with the function gen output to

provide a suitable load for the generator. Coil Z is too low. (will work without but

risk long term burn out of func. Gen.



To demonstrate magnetic fields, and allow students to visualise and understand the physics of magnetism


Lab Handout

Lab Report I