V

VOLT (V) The volt is the unit used in the measurement of electromotive force (electrical “pressure”). A standard electrical definition of the volt is: an electromotive force of 1 volt is necessary to move a current of 1 ampere through a 1 Ω resistor. It is often also referred to as electrical potential difference or potential difference.

VOLTAGE A measure of the force or "push" given the electrons in an electrical circuit; a measure of electrical potential. Analogy: pressure in a water pipe. AKA Potential.

VOLTAGE DROP Loss of voltage (electrical pressure) caused by the resistance in wire and electrical devices. Proper wire sizing will minimize voltage drop, particularly over long distances. Voltage drop is determined by four factors: wire size, current (amps), voltage, and length of wire. Water analogy: friction loss in pipe.

VOLTAGE, NOMINAL A way of naming a range of voltage to a standard. Example: A “12 volt nominal” system may operate in the range of 10 to 20 Volts. We call it “12 volts” for simplicity.

VOLTAGE, OPEN CIRCUIT See OPEN CIRCUIT VOLTAGE

VOLTAGE, PEAK POWER POINT (Vpp) The voltage at which a photovoltaic module or array generates at the highest power (watts). A “12 volt nominal” PV module will typically have a peak power voltage of around 17 volts. A PV array-direct solar pump should reach this voltage in full sun conditions. In a higher voltage array, it will be a multiple of this voltage.

VOLTMETER A device for measuring the voltage difference between any two points in an electrical circuit.