请输入您要查询的英文单词：

　

单词 ohm's law
释义

Ohm's law


Ohm's law

O0047150 (ōmz)n. The law stating that the direct current flowing in a conductor is directly proportional to the potential difference between its ends. It is usually formulated as V = IR, where V is the potential difference, or voltage, I is the current, and R is the resistance of the conductor.
[After Georg Simon Ohm.]

Ohm's law

n (General Physics) the principle that the electric current passing through a conductor is directly proportional to the potential difference across it, provided that the temperature remains constant. The constant of proportionality is the resistance of the conductor

Ohm's law

A law stating that the current in an electric circuit is equal to the voltage divided by the resistance. The current increases as the voltage increases, but decreases as the resistance increases.
Thesaurus
Noun1.Ohm's law - electric current is directly proportional to voltage and inversely proportional to resistance; I = E/Rlaw of nature, law - a generalization that describes recurring facts or events in nature; "the laws of thermodynamics"

Ohm's law


Ohm's law

(ōm) [for G. S. OhmOhm, Georg Simon
, 1787–1854, German physicist. He was professor at Munich from 1852. His study of electric current led to his formulation of the law now known as Ohm's law. The unit of electrical resistance (see ohm) was named for him.
..... Click the link for more information. ], law stating that the electric current i flowing through a given resistance r is equal to the applied voltage v divided by the resistance, or i=v/r. For general application to alternating-current circuits where inductances and capacitances as well as resistances may be present, the law must be amended to i=v/z, where z is impedanceimpedance,
in electricity, measure in ohms of the degree to which an electric circuit resists the flow of electric current when a voltage is impressed across its terminals.
..... Click the link for more information. . There are conductors in which the current that flows is not proportional to the applied voltage. These do not follow this law and are called nonohmic conductors.

Ohm's law

The direct current flowing in an electrical circuit is directly proportional to the voltage applied to the circuit. The constant of proportionality R, called the electrical resistance, is given by the equation below, in which V is the applied voltage and I is the current. Numerous deviations from this simple, linear relationship have been discovered. See Electrical resistance

Ohm’s Law

 

a law that states that the steady current density I in a conductor is directly proportional to the potential difference (voltage) U between two fixed points or cross sections of the conductor:

(1) RI = U

The proportionality constant R, which depends on the geometric and electric properties of the conductor and on temperature, is called the ohmic resistance, or simply the resistance, of the given section of the conductor. Ohm’s law was discovered in 1826 by the German physicist G. S. Ohm.

In the general case, the relationship between I and U is nonlinear; however, in practice it is always possible to assume it to be linear for a certain range of voltages and to apply Ohm’s law for this range. For metals and their alloys the range is virtually unlimited.

Ohm’s law in form (1) is valid for those sections of a circuit that do not contain any sources of electromotive force (emf). If such sources (storage batteries, thermocouples, or dynamos) are present, Ohm’s law assumes the form

(2) RI= U + E

where E is the emf of all sources connected in the section of the circuit that is being considered. For a closed circuit, Ohm’s law assumes the following form:

(3) RtI = E

where Rt = R + Ri is the total resistance of the entire circuit, which is equal to the sum of the external resistance R of the circuit and the internal resistance Ri of the source of emf. Kirchhoff’s laws generalize Ohm’s law for the case of branched circuits.

Ohm’s law can also be written in differential form, which links the current density j and the total electric field strength for each point of the conductor. The potential electric field of intensity E generated in conductors by the microscopic charges—electrons and ions—of the conductors themselves cannot support steady motion of free charges (a current), since the work done by the field in a closed loop is equal to zero. The current is supported by nonelectrostatic forces of various origins (induction, chemical, thermal, and so on) that are active in the emf sources and can be represented as some equivalent, nonpotential field of intensity Eext, called the external field. In the general case, the total strength of the field acting on the charges in the conductor is E + Eext. Correspondingly, the differential Ohm’s law assumes the form

(4) ρj = E + Eext or j = σ(E + Eext)

where ρ is the specific electric resistivity of the conductor material and σ = 1/ρ is the specific electrical conductivity.

Ohm’s law in complex form is also valid for sinusoidal quasi-stationary currents:

(5) ZI = E

where Z is the total complex impedance, equal to R + iX, and R and iX are the resistance and reactance of the circuit, respectively. If an inductance L and a capacitance C are present in a circuit carrying a quasi-stationary current of frequency ω, then X= ωL - 1/ωC.

REFERENCES

Kursfiziki, vol. 2. Edited by N. D. Papaleksi. Moscow-Leningrad, 1948.
Kalashnikov, S. G. Elektrichestvo. Moscow, 1964. (Obshchii kurs fiziki, vol. 2.)
Fizicheskie osnovy elektrotekhniki. General editor, K. M. Polivanov. Moscow-Leningrad, 1950.

Ohm's law

[′ōmz ‚lȯ] (electricity) The law that the direct current flowing in an electric circuit is directly proportional to the voltage applied to the circuit; it is valid for metallic circuits and many circuits containing an electrolytic resistance.

Ohm's law

The direct current flowing in an electrical circuit is directly proportional to the voltage applied to the circuit. The constant of proportionality R, called the electrical resistance, is given by the equation below, in which V is the applied voltage and I is the current. Numerous deviations from this simple, linear relationship have been discovered.

Ohm’s law

A law stating that the current in an electric circuit is directly proportional to the electromotive force (voltage) in the circuit and inversely proportional to the resistance in the circuit.

Ohm's law


Ohm's law

 [ōmz] a mathematical relationship formulated by the German physicist Georg Simon Ohm in 1826, comparing voltage (V), current (I), and resistance (R), usable for either current" >alternating current or current" >direct current. It originally applied only to situations of steady direct current, with the formula V = IR; with alternating current, the electrical circuit contains resistors, inductors, and capacitors and the formula becomes V = IZ, where Z is a complex number representing the impedance.

Ohm's law

(omz) [Georg S. Ohm, Ger. physicist, 1789–1854] The strength of an electric current, expressed in amperes, is equal to the electromotive force, expressed in volts, divided by the resistance, expressed in ohms (V=IR). See: electricity
LegalSeelawFinancialSeeOhm

Ohm's law


Related to Ohm's law: Kirchoff's Law
  • noun

Words related to Ohm's law

noun electric current is directly proportional to voltage and inversely proportional to resistance

Related Words

  • law of nature
  • law
随便看

　

英语词典包含2567994条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。

　

Copyright © 2004-2022 Newdu.com All Rights Reserved
更新时间：2024/11/14 18:51:37