Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

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Enclosed Lamp & Scale Galvanometer

Leeds & Northrup Co., Philadelphia

Humboldt State College, 1960

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Usage

The reflecting galvanometer is a sensitive instrument for measuring current. It consists of a magnet coil with an attached mirror suspended between the poles of a magnet by a thin gold ribbon above and a coiled gold wire below. When an electric current is introduced into the magnet coil it induces a magnetic field, causing the coil to rotate in proportion to the current. The mirror allows the user to see very small deflections, and thus to measure very small currents, by observing a distant reflected scale. In this instrument an illuminated image of a line is projected through a small telescope onto the mirror, which reflects it onto the built-in scale on the ground glass window on the front of the case.

The instrument on display in the case is from the physics department and is in new, unused condition. An identical instrument, seen in the web photo, was used in the physical chemistry lab. It was used by students in the physical/analytical chemistry laboratory at HSU for sensitive measurements in conjunction with the L&N K-3 Potentiometer as seen in the photograph from a 1963 HSC recruitment brochure.

 
Some contemporary/early descriptions of the galvanometer and its use are provided below:

Description

The instrument on display is in excellent, like-new condition. It is described in detail in the Cenco catalog description. The instrument is accompanied by an operating manual that is not on display, but may be viewed by clicking here.
 

From the Analytical/Physical Chemistry Lab - Exhibit Catalog

 HSTC icon
HSTC (1921-34)
HSC 54-73 icon
HSC (1954-1973)
HSC 35-53 icon
HSC (1935-1953)

HSC 1956-72 Instrument Collection

© R. Paselk
Last modified 11 August 20102010