The ohm (symbol: Ω) is the SI unit of electric resistance. The International System of Units (abbreviated SI from the French language name Système International dUnités) is the modern form of the metric system. ...
Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ...
Definition An ohm is a resistance that produces a potential difference of one volt when a current of one ampere is flowing through it. The volt (symbol: V) is the SI derived unit of electric potential difference. ...
The ampere (symbol: A) is the SI base unit of electrical current equal to one coulomb per second. ...
- 1 Ω = 1 V/A = 1 m2·kg·s–3·A–2
Origin The ohm is named after Georg Ohm, a German physicist who discovered the relation between voltage and current, expressed in Ohm's Law. Georg Ohm Georg Simon Ohm, (March 16, 1787,(or 1789) Erlangen, Germany - July 6, 1854,Munich) German physicist, was born in Erlangen and educated at the university there. ...
Since antiquity, people have tried to understand the behavior of matter: why unsupported flowers drop to the ground, why different materials have different properties, and so forth. ...
This article may be too technical for most readers to understand. ...
In electricity, current refers to electric current, which is the flow of electric charge. ...
Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or voltage drop (V) between the ends of a conductor and the current (I) flowing through the conductor are proportional at a given temperature: The equation contains the proportionality constant R, which is the electrical...
Explanation
 R is 1 ohm if V = 1 volt and I = 1 ampere By definition from Ohm's Law, a device has a resistance of one ohm if a voltage of one volt causes a current of one ampere to flow (R = V/I). Alternatively and equivalently, a device that dissipates one watt of power with one ampere of current flowing through it has a resistance of one ohm (R = P/I2). Image File history File links A voltage source, V, driving a resistor, R, and creating a current I. Useful for describing Ohms law or voltage sources. ...
Image File history File links A voltage source, V, driving a resistor, R, and creating a current I. Useful for describing Ohms law or voltage sources. ...
Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or voltage drop (V) between the ends of a conductor and the current (I) flowing through the conductor are proportional at a given temperature: The equation contains the proportionality constant R, which is the electrical...
A Device can be taken to mean: an electrical device designed to carry power, but not use it. ...
Since 1990, the ohm has been maintained internationally using the quantum Hall effect, where a conventional value is used for the 'von-Klitzing constant', fixed by the 18th General Conference on Weights and Measures as R{K-90} = 25812.807 Ω. This article is about the year. ...
The quantum Hall effect is a quantum-mechanical version of the Hall effect, observed in two-dimensional systems of electrons subjected to low temperatures and strong magnetic fields, in which the Hall conductance σ takes on the quantized values where e is the elementary charge and h is Plancks constant. ...
Klaus von Klitzing, (born June 28, 1943 in Schroda, Posen) is a Polish-German physicist. ...
The Conférence générale des poids et mesures (General Conference on Weights and Measures or CGPM) is one of the three organizations established to maintain the SI system under the terms of the Metre Convention (1875). ...
The complex quantity impedance is a generalisation of resistance. Its real part is resistance and its imaginary part is reactance. Impedance, resistance and reactance all have units of ohms. In mathematics, a complex number is an expression of the form a + bi, where a and b are real numbers, and i stands for the square root of minus one (−1), which cannot be represented by any real number. ...
In electrical engineering, Impedance is a measure of opposition to a sinusoidal electric current. ...
In the analysis of an alternating-current electrical circuit (for example a RLC series circuit), reactance is the imaginary part of impedance, and is caused by the presence of inductors or capacitors in the circuit. ...
The symbol for the ohm is the Greek capital letter omega (Ω). If the Greek letter cannot be used, the word ohm is used instead. The various guides for the use of the International System of Units (such as the official SI brochure and NIST Special Publication 811) do not explicitly forbid the elision of the final "o" of some SI prefixes, although there is nothing in them to suggest that it is allowable, either. As a result, one is just about as likely to see "kilohm", "kiloohm" and even "kilo-ohm", and the same holds true for hecto-, micro-, nano-, pico-, femto-, atto-, zepto-, and yocto-. The only other SI unit to suffer from this kind of orthographic uncertainty is the ampere. In the particular case of the ohm, one even sees the "a" prefixes lose that vowel: hence megohm and gigohm. Higher prefixes are rarely used with ohm. In the other direction, milliohms (or millohms) are seen where the resistance of cables, etc., are measured. Omega (Ω ω) (literally, big O) is the 24th and last letter of the Greek alphabet. ...
The ampere (symbol: A) is the SI base unit of electrical current equal to one coulomb per second. ...
Conversions A measurement in ohms is the reciprocal of a measurement in siemens, the SI unit of electrical conductance. Note that 'siemens' is both singular and plural. The reciprocal of the ohm is also called the mho, from ohm written backwards. The siemens (symbol: S) is the SI derived unit of electric conductance. ...
Electrical conductance is the reciprocal of electrical resistance. ...
The word singular may refer to one of several concepts. ...
Look up Plural on Wiktionary, the free dictionary Plural is a grammatical number, typically referring to more than one of the referent in the real world. ...
The siemens (symbol: S) is an SI derived unit of measurement for electric conductance, being the inverse of the ohm (Ω), named after Werner von Siemens. ...
See also Ohms law, named after its discoverer Georg Ohm [1], states that the potential difference or voltage drop (V) between the ends of a conductor and the current (I) flowing through the conductor are proportional at a given temperature: The equation contains the proportionality constant R, which is the electrical...
Resistor symbols A resistor is a two-terminal electrical or electronic component that resists the flow of current, producing a voltage drop between its terminals in accordance with Ohms law. ...
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