ampere

(noun)

A unit of electrical current; the standard base unit in the International System of Units. Abbreviation: amp. Symbol: A.

Related Terms

  • electrical current
  • current
  • ohm
  • magnetic field

Examples of ampere in the following topics:

  • Magnetic Force Between Two Parallel Conductors

    • The force between current-carrying wires is used as part of the operational definition of the ampere.
    • For parallel wires placed one meter away from one another, each carrying one ampere, the force per meter is:
    • Incidentally, this value is the basis of the operational definition of the ampere.
    • This means that one ampere of current through two infinitely long parallel conductors (separated by one meter in empty space and free of any other magnetic fields) causes a force of 2×10-7 N/m on each conductor.
  • Current and Voltage Measurements in Circuits

    • where I is the current through the conductor in amperes, V is the potential difference measured across the conductor in volts, and R is the resistance of the conductor in ohms (Ω).
    • To solve this problem, we would just substitute the given values into Ohm's law: I = 1.5V/5Ω; I = 0.3 amperes.
  • Overview of Electric Current

    • The SI unit for current is the ampere (A), named for the French physicist André-Marie Ampère (1775–1836).
    • Since I=ΔQ/Δt, we see that an ampere is one coulomb per second:
    • An ampere is the flow of one coulomb through an area in one second.
  • The Junction Rule

    • This law is founded on the conservation of charge (measured in coulombs), which is the product of current (amperes) and time (seconds).
  • Parallel-Plate Capacitor

    • Capacitors are limited in their ability to prevent charge flow from one conductive surface to the other; their ability to hold charge is measured in Farads (F), which are defined as 1 ampere-second per volt, one joule per square volt and one Coulomb per volt, among other ways.
  • Electric Motors

    • where F is the force (in newtons, N), I is the current in the wire (in amperes, A), L is the length of the wire that is in the magnetic field (in m), and B is the magnetic field strength (in teslas, T).
  • Applications

    • Substituting values of resistance and emf from the figure diagram and canceling the ampere unit gives:
  • Energy Usage

    • The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage) difference of V is $P = \frac{QV}{t} = IV$, where Q is electric charge in coulombs, t is time in seconds, I is electric current in amperes, and V is electric potential or voltage in volts.
  • Voltmeters and Ammeters

    • The name is derived from the name for the SI unit for electric current, amperes (A).
  • Electric Currents and Magnetic Fields

    • where the magnetic field is integrated over a curve (circumfrence of a wire), equivalent to integrating the current density (in amperes per square meter, Am-2) over the cross section area of the wire (which is equal to the permeability constant times the enclosed current Ienc).
Subjects
  • Accounting
  • Algebra
  • Art History
  • Biology
  • Business
  • Calculus
  • Chemistry
  • Communications
  • Economics
  • Finance
  • Management
  • Marketing
  • Microbiology
  • Physics
  • Physiology
  • Political Science
  • Psychology
  • Sociology
  • Statistics
  • U.S. History
  • World History
  • Writing

Except where noted, content and user contributions on this site are licensed under CC BY-SA 4.0 with attribution required.