Observing the Hall Effect *WIP*

In an effort to replicate the experiment Edwin Hall used to discover the Hall Effect on October 28 1879, I designed and laser cut an acrylic holder to secure a thin foil to wires.

In my initial searches I had trouble finding illustrations of the setup originally used by Hall. However after building the initial acrylic holder above I finally found it. As well as a very good paper on the experiment from 1979 in Phys Educ. Vol. 14

Hall 1880
Hall Experiment Vector
Click to download SVG

Parameters of the more quantitative experiment as run on November 12 1879:

  • Measurement equipment: (high resistance) Thomson (Mirror) Galvanometer
  • Current source: Bunsen cell
    • ~1.9v ??
  • Experiment substrate: Glass (soda lime, borosilicate?)
  • Conductor: Thin gold leaf
    • Conductor size: 2x9cm
  • Length of gold leaf exposed between the two connectors: 5.5cm
    • Resistance of exposed area: ~2ohms
  • Connectors/clamps: Brass blocks (polished on the underside)
  • Wires of current source connected to brass blocks: Soldered
  • Number of magnets used: 2
    • Magnet 1: "soft cemented" to the underside of the glass substrate
    • Magnet 2: Held ~6mm above the gold leaf

The results obtained by Hall in the above experiment

Current (C) [through] Magnetic field (M) Current (c) [across]
0.0616 11420 H 2.32x10^-9
0.0249 11240 H 8.5x10^-10
0.0389 11069 H 1.35x10^-9
0.0598 7670 H 1.47x10^-9
0.0595 5700 H 1.04x10^-9

H = "horizontal intensity of earth's magnetic field" the approximated at .19

Something one has the wonder about are the units of these numbers, especially in units commonly used today (2019)
The "C" unit is probably Coulombs, or more accurately Coulombs per second (C/s) which is now known as an Ampere. 2
Magnetic field "M" would appear to be magnetization or ampere per meter (A/m), the same as H-field 3 which then explains the use of "H" being the same (A/m)

With more conventional units used today

  • Switching to Amperes and scaling with milliamperes for the current in
  • Switching to Amperes and scaling with nanoamperes for the current out
Current (mA) [through] Magnetic field (M) Current (nA) [across]
61.6 11420 H 2.32
24.9 11240 H 0.85
38.9 11069 H 1.35
59.8 7670 H 1.47
59.5 5700 H 1.04

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