Georg Simon Ohm (16 March 1789 - 6 July 1854) was a German physicist and mathematician. During part of the time in his life, Ohm worked as a school teacher. Some of his research focused on the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment he had created himself, Ohm found that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current. This relationship is known as Ohm's law.