What does an ammeter measure?

An ammeter is a device specifically designed to measure electric current flowing through a circuit. It is typically connected in series with the circuit to allow the current to flow directly through the ammeter, providing an accurate reading of the current measured in amperes (A). The design of an ammeter ensures minimal impact on the circuit's operation, and it is calibrated to display the current level directly.

Understanding the role of each of the other devices can help clarify why they do not provide the same function as an ammeter. Voltage is measured by a voltmeter, which is connected in parallel with the component of interest, thus it does not measure current. Resistance is determined using an ohmmeter, which also requires disconnection from the power source. Power is typically calculated using the relationship between current and voltage, usually demonstrated through tools like a wattmeter rather than being directly measured by an ammeter. Hence, an ammeter's sole purpose is to measure current, making it essential for various electrical applications and diagnostics.