Immagini

DESCRIPTION

Exhibit 633 is an astatic galvanometer for measuring current values. The instrument has a circular wood base with four wood legs which supports a brass column curved at the top to provide a hook positionead over the center of the base. A wire hung from the hook supports an astatic system (see ref ^[1]) formed by two counter-oriented magnetic needles so as not to be influenced by the earth's magnetic field. The upper needle rotates over a paper square (the original is missing) attached to the rectangular frame of the fixed coil which constituted the dial. On the same frame there are the two terminals for external connection. The entire galvanometer is covered by a large bell jar which fits in the round slot of the base and protects the galvanometer from external perturbations.

This instrument needed a calibration with a known current source. See ref ^[2]

ISCRIZIONI

1. Sulla bobina di legno è scritto in inchiostro: Resistenza di questo telaio Ohm 6,41

BIBLIOGRAPHY

• [1] Privat - Dessschanel, "Trattato elementare di Fisica", Milano, Fratelli Dumolard, 1882. §548, pag. 516
• [2] Giovanni Boato - Giuseppe Bruzzanti,"Strumenti nella Fisica dell'Ottocento", Uiversità degli studi di Genova; §64, pag. 57.

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