Description
The Galvanometer

The galvanometer is one of the earliest electrical measuring instruments and was invented by Leopold Nobili (1784-1835). A galvanometer functions through the heating effect of a current (using either a wire or a thermocouple) and it is used to measure electrical currents. Measuring devices such as the galvanometer were important to scientists as they tried to understand electricity and eventually use it.

The galvanometer measures current, which is the quantity of charge moving past a certain point per unit of time. The galvanometer used magnetized needles and copper wire in the form of a coil to achieve this.

The galvanometer on display in the electrical case as shown opposite is a modified design by Andre Broca, who was the Professor of Physics at L'Ecole Polytechnique in Paris. Broca increased the strength of the magnetic poles at the center of the coil using a special arrangement.

Before the invention of the galvanometer the most sensitive indicator of electric current was freshly prepared frog's legs which would twitch when a current was applied to them.

In the 1840's there was a great demand for galvanometers due to a rapidly expanding electrical industry. Many developments in galvanometers were made and the galvanometer was reproduced by many instrument makers all over Europe. Charles Wheatstone had a version made by Watkins and Hill in 1845 so that he could conduct experiments on the velocity of electricity.