Image: Tangent galvanometer Philip-Harris top1

Description: en:Tangent galvanometer made by en:Philip Harris Ltd., Birmingham, England, ca. 1950. From the Sammlung historischer Messtechnik (Collection of historical measurement apparatus), A. Kusdas. In the middle of the galvanometer is a compass that is aligned to be horizontal using the brass leveling screws. The black ring has a diameter of 17 cm; it houses a circular coil of wire. In use, the galvanometer is rotated on a table so that this ring is parallel to the direction of the earth's local magnetic field, and the compass needle will be parallel to the ring. As can be seen, the apparatus was not aligned when the photograph was taken. When a source of electrical current is hooked up to the coil, the resulting magnetic field causes the compass needle to rotate away from its initial alignment parallel to the coil. The angle of rotation is used to calculate the current through the coil.
Title: Tangent galvanometer Philip-Harris top1
Credit: http://www.historische-messgeraete.de/images/gb_philip-harris_tangent-galvanometer1_top1.jpg
Author: Alexander Kusdas
Permission: Lizenzbestimmungen (in German). Sammlung historischer Messtechnik. Retrieved on 2012-12-20. Licensing for re-use of text and photographs from the website http://www.historische-messgeraete.de is offered under the German version of the CC-BY-SA 3.0.
Usage Terms: Creative Commons Attribution-Share Alike 3.0
License: CC BY-SA 3.0
License Link: http://creativecommons.org/licenses/by-sa/3.0
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