What device is used to measure current in a circuit?

• A. Voltmeter
• B. Ammeter
• C. Ohmmeter
• D. Wattmeter

Answer: (B)

An ammeter is specifically designed to measure the flow of electric current in a circuit, providing readings in amperes (A). It functions by allowing the current to pass through it, thereby enabling it to calculate the intensity of the current in the circuit. When connected in series with the circuit, it offers an accurate measurement of current because it effectively incorporates the complete flow of electric charge.

In contrast, a voltmeter measures the electrical potential difference between two points in a circuit, displaying results in volts. An ohmmeter assesses the resistance in ohms, which is critical for analyzing how much opposition there is to current flow in a component or circuit path. Finally, a wattmeter measures electrical power in watts, which is a product of voltage and current and not a direct measurement of current itself. Each of these devices serves a distinct purpose in electrical measurements, reinforcing why the ammeter is the correct choice for measuring current.