Immagini

DESCRIPTION

Exhibit 423 is L-C bridge designed by Anderson, improved by Fleming and used for measuring auto-inductance. According to Anderson, one inserts a known capacitance and determines the inductance by balancing the bridge in terms of the capacitance and the four resistances independent of the frequency.  ^[1],

The method of Anderson was then perfected by Fleming to measure small inductances (of the order of μH) using small capacitances.  ^[2]

The instrument appears as a large case with 12 knobs: 11 corresponding to variable resistances of different maximum values and a three-way commutator (choice between galvanometer and head phones). There are 6 couples of terminals for external connections: 2 for the condenser, 2 for the inductance to measure, 2 for the galvanometer, 2 for connection to a alternating voltage source, 2 for the head phones and 2 incribed with "F" which are connected together with a metal bar. The case is completely closed but has four openings in the side walls covered with mesh.

ISCRIZIONI

1. Allocchio Bacchini - Milano inciso sulla superficie superiore

BIBLIOGRAPHY

• [1] Anderson, " Phil. Mag." (3) 31, p. 329, 1891.
• [2] Fleming, "Phil. Mag.", (6), 7, p. 586, 1904.

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