Which unit would measure the current in a circuit?

• A. Volts
• B. Ohms
• C. Watts
• D. Amperes (amps)

Answer: (D)

Current is the rate at which electric charges flow through a circuit, so the unit used to measure it is the ampere. An ampere, or amp, represents one coulomb of charge passing a point each second. That’s why the unit for current is amperes.

Volts measure electrical potential difference, ohms measure resistance, and watts measure power, not current. In practical terms, if you want to know how much charge is flowing per second, you’d read in amperes (often with an ammeter placed in series in the circuit).