An ammeter is an electrical instrument used to measure the flow of electric current in a circuit. It is typically connected in series with the circuit, allowing it to measure the current flowing through it in amperes (A). Ammeters can be analog, using a needle and dial to display readings, or digital, providing numerical values on a screen. These devices are essential in various applications, including electronics, engineering, and research, as they help ensure that circuits operate within safe and efficient current levels. Understanding how to use an ammeter is crucial for anyone working with electrical systems, including electricians and engineers.