Ampere-meter

1. What is an Ammeter?

   • Ammeters are used to measure the current in electricity in amperes. Named after French scientist Andre-Marie Ampere, amperes are a unit of measurement for determining the amount of electricity moving through a circuit. Ampere's Law simply states that the magnetic field within a closed loop is proportional to the electric current in that loop.

   How Ammeters Work

   • Ammeters can thus be used to measure this current by having electric current move through a set of coils. In moving-coil ammeters, this movement results from the fixed magnets that are set opposite to the current. The movement then turns a centrally located armature that is attached to an indicator dial. This dial is set above a graduated scale that lets the operator know how much current is moving through a closed circuit, as stated by writers at the Ammeter Gauge website.

   Types of Ammeters

   • There are various types of ammeters. One called the d'Arsonval ammeter, which uses the fixed magnet discussed above, also uses a galvanometer through which an electric current passes. Ammeters used to measure high frequency currents utilize the heat created by the electrical current that moves through the coils. The heat is detected by thermocouples, which helps drive a moving-coil indicator.

   Uses for Ammeters

   • Ammeters have various applications where they can be used to read alternating current, AC or direct current, DC. They are often used in cars where they measure DC. It should be noted that ammeters and voltemeters are often producted as a single instrument and may digitally display current with very high accuracy, as mentioned by the writers at World of Invention.