
4 0 c m
34cm
actual image size: 26cm x 32cm
Description
Tangent galvanometers measure current using Hans Christian oersted's 1820 discovery of the magnetic effect produced by an electric current. The galvanometer is turned until the coil points the same way as the compas needle. Current pasing through the coil then creates a magnetism at right angles to the magneticism of the Earth, and the needle swings to a new angle which shows the strength of the current.
Image Details
Image Ref.
10326061
© Science Museum / Science & Society Picture Library