what is an ammeter

An ammeter is an instrument used to measure the current in a circuit, which is measured in amperes (A) . It is designed to be placed in series with a circuit element to measure the electric current flow through it. An ammeter usually has low resistance so that it does not cause a significant voltage drop in the circuit being measured. Ammeters must not be connected directly across a voltage source since their internal resistance is very low and excess current would flow. There are different types of ammeters that vary in their operating principles and accuracies, such as the D’Arsonval-movement ammeter and the electrodynamic ammeter. A portable hand-held clamp-on ammeter is a common tool for maintenance of industrial and commercial electrical equipment, which is temporarily clipped over a wire to measure current. The instrument most commonly used to measure current is the ammeter.