# Volt

Josephson junction array chip developed by NIST as a standard volt.
The volt (symbol: V) is the SI derived unit of electric potential difference or electromotive force.[1][2] It is named in honor of the Italian 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.

#### 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{J-90} = 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, the rate of which is determined by the voltage, and the total output measured in watts. The equation that brings all three components together is: volts × amperes = watts

## Common voltages

A multimeter can be used to measure the voltage between two points

1.5 V C-cell batteries

Nominal voltages of familiar sources:
Note: Where 'RMS' (root mean square) is stated above, the peak voltage is 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. 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.

 This SI unit is named after Alessandro Volta. As for all SI units whose names are derived from the proper name of a person, the first letter of its symbol is uppercase (V). But when an SI unit is spelled out, it should always be written in lowercase (volt), unless it begins a sentence or is the name "degree Celsius". — Based on The International System of Units, section 5.2.

## References

1. ^ SI Brochure, Table 3 (Section 2.2.2). BIPM (2006). Retrieved on 2007-07-29.
2. ^ Rudolf F. Graf, "Volt", Dictionary of Electronics; Radio Shack, 1974-75. Fort Worth, Texas. ISBN B000AMFOZY

SI derived units are part of the SI system of measurement units and are derived from the seven SI base units.

## Dimensionless derived units

The following SI units are actually dimensionless ratios, formed by dividing two identical SI units.
plug-in hybrid electric vehicle (PHEV) is a hybrid vehicle with batteries that can be recharged by connecting a plug to an electric power source. With an internal combustion engine and batteries for power, they share the characteristics of conventional hybrid electric vehicles and
A concept car or show car is a car prototype made to showcase a concept, new styling, technology and more. They are often shown at motor shows to gauge customer reaction to new and radical designs which may or may not have a chance of being produced.
It is likely to contain information of a speculative nature, though such must be attributed to relevant sources. Concept cars, by definition, rarely become production models, and any given specifications may change
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Volts is an album by AC/DC released as a part named "Disc Four" on the Bonfire box set.
Si, si, or SI may refer to (all SI unless otherwise stated):

In language:
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SI derived units are part of the SI system of measurement units and are derived from the seven SI base units.

## Dimensionless derived units

The following SI units are actually dimensionless ratios, formed by dividing two identical SI units.
In physics, the potential difference is a quantity related to the amount of energy that would be required to move an object from one place to another against various types of forces.
Electromotive force (emf, ) is a term used to characterize electrical devices, such as voltaic cells, thermoelectric devices, electrical generators and transformers, and even resistors.
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physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena spanning all length scales: from the sub-atomic particles from which all ordinary matter is made (particle physics) to the behavior of the material Universe as a whole
Alessandro Volta

Alessandro Giuseppe Antonio Anastasio Volta (1745-1827)
Born January 18 1745
Como, Lombardy, Italy
Voltaic pile is the first modern electric battery, invented by Alessandro Volta in 1800. Volta demonstrated that when metals and chemicals come into contact with each other they produced an electrical current.
battery is a device consisting of one or more electrochemical cells, which store chemical energy and make it available in an electrical form. There are many types of electrochemical cells, including galvanic cells, electrolytic cells, fuel cells, flow cells, and voltaic cells.
In physics, the potential difference is a quantity related to the amount of energy that would be required to move an object from one place to another against various types of forces.
Electric current is the flow (movement) of electric charge. The SI unit of electric current is the ampere (A), which is equal to a flow of one coulomb of charge per second.

## Definition

The amount of electric current (measured in amperes) through some surface, e.g.
ampere, in practice often shortened to amp, (symbol: A) is a unit of electric current, or amount of electric charge per second. The ampere is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
WATT

Branding NewsTalk 1240
First air date 1945
Frequency 1240 kHz
Format News-Talk-Sports
Power 1,000 watts
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In physics, power (symbol: P) is the rate at which work is performed or energy is transmitted, or the amount of energy required or expended for a given unit of time.
1 metre =
SI units
1000 mm 0 cm
US customary / Imperial units
0 ft 0 in
The metre or meter[1](symbol: m) is the fundamental unit of length in the International System of Units (SI).
kilogram or kilogramme (symbol: kg) is the SI base unit of mass. The kilogram is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
second (SI symbol: s), sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units (SI) base unit of time.

SI prefixes are frequently combined with the word second to denote subdivisions of the second, e.g.
ampere, in practice often shortened to amp, (symbol: A) is a unit of electric current, or amount of electric charge per second. The ampere is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
The joule (IPA: [dʒuːl] or [dʒaʊl]) (symbol: J) is the SI unit of energy.
energy (from the Greek ενεργός, energos, "active, working")[1] is a scalar physical quantity that is a property of objects and systems of objects which is conserved by nature.
The coulomb (symbol: C) is the SI unit of electric charge. It is named after Charles-Augustin de Coulomb.

## Definition

1 coulomb is the amount of electric charge transported by a current of 1 ampere in 1 second.