Ohm’s Law is a mathematical formula that expresses the relationship between the Potential difference, electric current, and resistance in a circuit. The German Physicist, George Ohm discovered this relationship in 1826 (Cutnell & Johnson 1998, p. 590). When applied to a direct-current circuit, Ohm’s Law states, that the electromotive force (E) measured in volts =the current (I) in amperes multiplied by the resistance (R) in ohms;
Therefore E = IR. …. (1)
When the law is used for an alternating-current circuit, resistance is replaced by impedance (Z), also in ohms. “The flow of alternating current produces a counter electromotive force, which resists the current†(Cutnell & Johnson 1998, p. 591). The strength of such resistance depends on how rapidly the current alternates. Impedance consists of resistance, called reactants n combined with the circuits’ regular resistance to direct current.
