# Electrical Devices and Terms Glossary

Ammeter an instrument for measuring electric current in amperes.
Ampere
Is a unit of electric current; ampere is often shortened to “amp”. It is the basic unit of electric current in the International System of Units and was named after André-Marie Ampère, French mathematician and physicist, considered the father of electrodynamics. Wikipedia

Ballistic galvanometer Moving coil galvanometer was developed independently by Marcel Deprez and Jacques-Arsne d’Arsonval about 1880. Deprez’s galvanometer was developed for high currents, while D’Arsonval designed his to measure weak currents. The moving coil galvanometer is practically immune to ambient magnetic fields is constructed in a manner very similar to ammeter.

Frequency

Multimeter The meter movement in a moving pointer analog multimeter is practically always a moving-coil galvanometer of the d’Arsonval type, using either jeweled pivots or taut bands to support the moving coil. In a basic analog multimeter the current to deflect the coil and pointer is drawn from the circuit being measured; it is usually an advantage to minimize the current drawn from the circuit.

Moving coil galvanometer was developed independently by Marcel Deprez and Jacques-Arsène d’Arsonval about 1880. Deprez’s galvanometer was developed for high currents, while D’Arsonval designed his to measure weak currents. The moving coil galvanometer is practically immune to ambient magnetic fields. This moving coil galvanometer is mainly used to measure very feeble or low currents of order 10−9 A.

Tesla Coil

Voltage

Voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.  A moving coil galvanometer can be used as a voltmeter by inserting a resistor in series with the instrument.