Volt: SI Derived Unit, Electromotive Force, Voltage, Alessandro Volta, Battery, Baghdad Electric Current, Ampere, Power, Josephson Effect

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In the water flow analogy sometimes used to explain electric circuits by comparing them to water-filled pipes, voltage difference is likened to water pressure difference - the difference determines how quickly the electrons will travel through the circuit. Current (in amperes), in the same analogy, is a measure of the volume of water that flows past a given point per unit time (volumetric flow rate). The flow rate is determined by the width of the pipe (analogous to electrical resistance), and the pressure difference between the front end of the pipe and the exit is analogous to voltage. The analogy extends to power dissipation: the power given up by the water flow is equal to flow rate times pressure, just as the power dissipated in a resistor is equal to current times the voltage drop across the resistor (amperes x volts = watts).