Electrical engineering credited with establishing the term "electricity". He also designed the versorium: a device that detects the presence of statically charged objects. In 1762 Swedish professor Johan Carl Wilcke invented a device later named electrophorus that produced a static electric charge. By 1800 Alessandro Volta had developed the voltaic pile, a forerunner of the electric battery In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, of Michael Faraday (the discoverer of electromagnetic
Volta potential electrostatic potentials, but instead the difference in Fermi level between the two materials, a difference that is exactly zero at equilibrium. The Volta potential however corresponds to a real electric field in the spaces between and around the two metal objects, a field generated by the accumulation of charges at their surfaces. The total charge formula_2 over each objects' surface depends on the capacitance formula_3 between the two objects, by the relation formula_4 where formula_5 is the Volta potential. It follows therefore that the value of the potential can be measured by varying the capacitance between the materials by a