Galvanometer

Astronomy

Accession Number: 2018.ast.69 (DAA-0024)

Description:

This object is a mirror galvanometer. It consists of a rectangular insulating base with four plastic feet. At the front of the base there are two electrical contacts with knurled plastic knobs on the top so wires can be affixed.

A large horseshoe magnet lies flat on the base, with the ends towards the electrical contacts. Between these two ends there are chunky metal attachments attached with screws which almost behind a tall rectangular mirror. Between the two there is a notch, where there appears to be a space for the suspension of a wire. However, no wire or mirror is visible. Just behind this, sitting on top of the magnet, there is a rectangular piece of insulating material with felt on the lower side.

Coming out of the top of the window section there is a knob with a wire attached. This wire is strung across to a tall thin cylindrical object located in the curve of the horseshoe magnet.

Alternative Name:

Mirror galvanometer, suspension galvanometer

Markings:

Engraved on the frame of the window: “KIPP
DELFT HOLLAND”
“184A”

Engraved on the chunky metal attachment on the right-hand end of the horseshoe magnet: “11”

Dimensions (cm): Length: 22, Width: 14, Height: 15.5

Function:

This is a mirror galvanometer used for the measurement of very small changes in electrical current. Light is reflected on a small mirror in the interior (missing from this example). This mirror is connected to a fine wire which is affected by tiny shifts in electrical current. The amount of the deflection of the mirror can be used to measure electrical current.

Condition:

Very good: In places, the metal surface of the galvanometer is stained or marked with residue, possibly from tape. The wire and suspended mirror appears to be missing. Otherwise, the galvanometer is in very good condition.

Manufacturer: P.J. Kipp & Zonen, Delft, Holland

Date of Manufacture: 1930s

Provenance:

This object was likely moved from the David Dunlap Observatory in Richmond Hill in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.