Monday, October 23

OHM's Law

George Simon Ohm (1787-1854) gave his name to the unit of electrical resistance, the ohm and the law of electric current, Ohm's Law. Ohm, a German, linked his name with those of Ampere, and Volta, in formulating his famous law, which states that electric current is directly proportional to electromotive force and inversely to resistance; or expressed in the familiar equation: electromotive force (in volts) = current (in amperes) x resistance (in ohms).

Despite Ohm's great contribution to electrodynamics, you will rarely see his name on a piece of electrical equipment, along with Ampere, Volta and Watt.  The resistor (or resistance), a device used in electrical circuits, is marked in ohms, but by means of a color code (black, brown, red, orange, yellow, green, blue, violet, grey and white representing the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 respectively.)