US1822129 — System & Apparatus Employing the Hall Effect

U.S. Patent 1,822,129, "System & Apparatus Employing the Hall Effect," was granted to Palmer H. Craig on September 8, 1931. It generalizes Craig's 1926 Physical Review film measurements into a stacked-plate device intended to act as a rectifier, amplifier, oscillator, and detector.

Design

The device uses stacked insulated plates of bismuth, tellurium, or bismuth-antimony. The plates are connected in parallel at their ends and in series along the transverse axis, so that the transverse Hall potentials sum while the longitudinal current is shared. The patent gives the relation

E = HI/d

and names the Corbino Effect — radial current in a disc under a perpendicular field producing a circular current — as a related phenomenon.

Reported performance

• About 50 µV per film; about 200 µV with transverse series connection, under 4 A at 60 Hz through a 12-turn coil.
• "Several volts for only one milliampere flowing through the field coil and longitudinally through the conductive films in parallel."
• The patent asserts the device is a "perfect rectifier" producing no distortion; this is the inventor's claim, not an independently verified result.
• Stated to be usable as rectifier, amplifier, oscillator, and detector, and combinable with electron tubes.

Figures

The patent carries ten figures: Fig. 1 perspective; Fig. 2 end view showing field direction; Fig. 3 film arrangement; Fig. 4 rectifier wiring; Fig. 5 reflex receiving circuit; Fig. 6 detector circuit; Fig. 7 amplification/oscillation; Fig. 8 independent longitudinal-current source; Fig. 9 amplifier plus rectifier; Fig. 10 transverse field arrangement.

British counterpart

GB274112 describes rectification by transverse potential difference from a longitudinal current through conducting plates in a perpendicular magnetic field. Alternating current is passed longitudinally through parallel plates 1, 2, 3 separated by insulating sheets and through a solenoid S producing the perpendicular field; the transverse potentials are connected in series at edges e, j. Because both the longitudinal current and the field alternate, the transverse potential difference is direct. A modification etches conducting material on an insulating base so that two systems of films are in parallel longitudinally and in series transversely, placed side by side rather than stacked.

Status of the claims

The patent's own reported figures were not independently reproduced in the source. Harry F. Breckel's 1927 tests of the assembled device found the apparent rectification to be a thermal junction effect of a few millivolts with very low efficiency, with meter readings dominated by inductive pickup and radio reception results of zero. The patent describes current modification, not primary power generation, which is in tension with the dossier's "bismuth battery" framing.

See also

Hall-Effect Rectification, Additive Principle (Series Hall Potentials), comparisons/comparison-craig-hall-effect-claims-vs-evidence.