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The ampere (/ ˈæmpɛər / AM-pair, US: / ˈæmpɪər / AM-peer; [1][2][3] symbol: A), [4] often shortened to amp, [5] is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 coulomb (C) moving past a point per second. [6][7][8] It is named after French mathematician and physicist André-Marie ...
An ampere-hour or amp-hour (symbol: A⋅h or A h; often simplified as Ah) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs. [1][2] The commonly seen milliampere-hour (symbol: mA⋅h, mA h, often ...
In the International System of Units (SI), electric current is expressed in units of ampere (sometimes called an "amp", symbol A), which is equivalent to one coulomb per second. The ampere is an SI base unit and electric current is a base quantity in the International System of Quantities (ISQ).
The farad (symbol: F) is the unit of electrical capacitance, the ability of a body to store an electrical charge, in the International System of Units (SI), equivalent to 1 coulomb per volt (C/V). [1] It is named after the English physicist Michael Faraday (1791–1867). In SI base units 1 F = 1 kg −1 ⋅ m −2 ⋅ s 4 ⋅ A 2.
A domestic power supply voltage (110 or 230 V), 50 or 60 Hz alternating current (AC) through the chest for a duration longer than one second may induce ventricular fibrillation at currents as low as 30 milliamperes (mA). [12] [13] With direct current (DC), 90 to 130 mA are required at the same duration. [14]
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.
The coulomb is defined as the quantity of charge that passes through the cross section of an electrical conductor carrying one ampere for one second. [6] This unit was proposed in 1946 and ratified in 1948. [6] The lowercase symbol q is often used to denote a quantity of electric charge.
The ampere rapidly gained support over the ohm, as many national standards laboratories were already realizing the ampere in absolute terms using ampere balances. [ 16 ] [ 20 ] The International Electrotechnical Commission (IEC) adopted the Giorgi system with the ampere replacing the ohm in 1935, and this choice of base units is often called ...