| 释义 |
Ohm’s Law V = I × R or I = V/R The law of physics that defines the relationships between power, voltage, current, and resistance in linear constant-current circuits. Ohm’s Law states that the current (I) in an electric circuit is directly proportional to the electromotive force (emf), or voltage (E), applied to a circuit, and inversely proportional to the resistance (R) of the circuit.Another way of thinking of Ohm’s Law is that the current flowing through a wire is directly proportional to its cross-sectional area and inversely proportional to its length. So, for a circuit of a given metal at a given constant temperature, the thicker and shorter the wire, the less the resistance. Ohm’s Law is named for Georg Simon Ohm, its inventor. See also current, emf, resistance, and voltage. 74570c15.qxd 9/11/07 12:26 PM Page 348 |