What does an ammeter measure in an electrical circuit?

An ammeter is specifically designed to measure electric current flowing through a circuit, which is typically expressed in amperes (A). When connected in series within the circuit, it allows the flow of electricity to pass through it, enabling it to provide an accurate reading of the current. This is crucial for diagnosing issues in electrical systems, ensuring components operate within safe and expected current limits, and for performing calculations related to ohms law and power consumption.

The other options relate to different electrical measurements. Voltage levels refer to the electric potential difference and are measured in volts using a voltmeter. Electric power consumption, which is the rate at which electrical energy is used, is typically calculated by multiplying voltage and current but requires separate measurements rather than direct measurement with an ammeter. Resistance, measured in ohms, assesses how much a component opposes the flow of current and is measured using an ohmmeter, not an ammeter. Thus, C is the correct choice as it accurately defines the function of an ammeter in electrical applications.