# Dictionary Definition

volt n : a unit of potential equal to the potential difference between two points on a conductor carrying a current of 1 ampere when the power dissipated between the two points is 1 watt; equivalent to the potential difference across a resistance of 1 ohm when 1 ampere of current flows through it [syn: V]

# User Contributed Dictionary

## English

### Etymology

Named after the Italian physicist Alessandro Volta.

### Noun

1. In the International System of Units, the derived unit of electrical potential and electromotive force (voltage); the potential difference across a conductor when a current of one ampere uses one watt of power. Symbol: V

## French

### Pronunciation

• lang=fr|/vɔlt/
• SAMPA: /vOlt/

fr-noun m
1. volt

## Hungarian

### Etymology

From the same as Finnish and Estonian olla

volt

hu-noun ok
1. volt

volt (p: volt)
1. volt
2. volts

## Latin

### Verb form

volt
1. he wishes, he wants, he is willing (archaic form of vult, present active indicative third-person singular of velle)

## Swedish

### Noun

volt
1. A jump where one turns one or more times forwards (or backwards).
2. (generalization of above) The action where something of large size turns over. See slå en volt.
Bilen körde av vägen och slog en volt. = The car went off the road and turned over a whole turn.

volt

# Extensive Definition

The volt (symbol: V) is the SI derived unit of electric potential difference or electromotive force. It is named in honor of the Lombard physicist Alessandro Volta (1745–1827), who invented the voltaic pile, the first modern chemical battery.

## Definition

The volt is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power. Hence, it is the base SI representation m2 · kg · s-3 · A-1, which can be equally represented as one joule of energy per coulomb of charge, J/C.
\mbox = \dfrac = \dfrac = \dfrac = \dfrac = \dfrac

### Josephson junction definition

Since 1990 the volt is maintained internationally for practical measurement using the Josephson effect, where a conventional value is used for the Josephson constant, fixed by the 18th General Conference on Weights and Measures as
K = 0.4835979 GHz/µV.

## Hydraulic analogy

In the hydraulic analogy sometimes used to explain electric circuits by comparing them to water-filled pipes, voltage is likened to water pressure – it determines how fast 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 (potential difference or 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).
The relationship between voltage and current (in ohmic devices) is defined by Ohm's Law.

## Common voltages

Nominal voltages of familiar sources:
Note: Where 'RMS' (root mean square) is stated above, the peak voltage is \sqrt times greater than the RMS voltage for a sinusoidal signal centered around zero voltage.

## History of the volt

In 1800, as the result of a professional disagreement over the galvanic response advocated by Luigi Galvani, Alessandro Volta developed the so-called Voltaic pile, a forerunner of the battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver. In the 1880s, the International Electrical Congress, now the International Electrotechnical Commission (IEC), approved the volt for electromotive force. At that time, the volt was defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power.
Prior to the development of the Josephson junction voltage standard, the volt was maintained in national laboratories using specially constructed batteries called standard cells. The United States used a design called the Weston cell from 1905 to 1972.

## References

volt in Tosk Albanian: Volt
volt in Arabic: فولت
volt in Asturian: Voltiu
volt in Bengali: ভোল্ট
volt in Min Nan: Bó͘-lú-to͘h
volt in Belarusian: Вольт
volt in Belarusian (Tarashkevitsa): Вольт
volt in Bosnian: Volt
volt in Breton: Volt
volt in Bulgarian: Волт
volt in Catalan: Volt
volt in Czech: Volt
volt in Danish: Volt
volt in German: Volt
volt in Estonian: Volt
volt in Modern Greek (1453-): Βολτ
volt in Spanish: Voltio
volt in Esperanto: Volto
volt in Basque: Volt
volt in French: Volt
volt in Friulian: Volt
volt in Gan Chinese: 伏
volt in Galician: Volt
volt in Korean: 볼트
volt in Croatian: Volt
volt in Indonesian: Volt
volt in Icelandic: Volt
volt in Italian: Volt
volt in Hebrew: וולט
volt in Kurdish: Volt
volt in Latin: Voltium
volt in Latvian: Volts
volt in Lithuanian: Voltas
volt in Hungarian: Volt
volt in Macedonian: Волт
volt in Malay (macrolanguage): Volt
volt in Dutch: Volt (eenheid)
volt in Japanese: ボルト (単位)
volt in Norwegian: Volt
volt in Norwegian Nynorsk: Volt
volt in Polish: Wolt
volt in Portuguese: Volt
volt in Kölsch: Volt (Mohß)
volt in Romanian: Volt
volt in Russian: Вольт
volt in Scots: Volt
volt in Simple English: Volt
volt in Slovak: Volt
volt in Slovenian: Volt
volt in Serbian: Волт
volt in Serbo-Croatian: Volt
volt in Finnish: Voltti
volt in Swedish: Volt
volt in Tamil: வோல்ட்டு
volt in Thai: โวลต์
volt in Vietnamese: Vôn
volt in Turkish: Volt
volt in Ukrainian: Вольт
volt in Contenese: 伏
volt in Chinese: 伏特