Henry’s method

Experiment Setup


  1. Wrap a steel needle with insulated wire;
  2. Connect the wire with power supply operating under constant current mode. A small resistor of 2Ohm is connected in serial with the coil.


  1. Fix the compass on the table, record the initial position of compass needle;
  2. Put the tip of the steel needle at a fixed position (as marked in the figure), perpendicular with the initial orientation of compass needle;
  3. Read the deflection angle of compass needle;
Setup based on Henry’s method