Cavendish Laboratory : William Thomson's electostatic voltmeter

Cavendish Laboratory

<p style='text-align: justify;'>This instrument met the needs of the growing electrical industry. It made use of the force between two charged bodies, in this case insulated parallel plates, one set fixed and the other moveable. Using the different weights supplied with the instrument potential differences of 50 to 10,000 volts could be measured. Electrostatic meters had the advantage that they used no current and could work equally well with alternating and direct potential differences. (G. Green, J.T. Lloyd, 'Kelvin’s Instruments and the Kelvin Museum', Glasgow, 1970, pp. VII and 25-27)</p>