The ampere is the base unit for which electrical quantity?

• A. Voltage
• B. Resistance
• C. Current
• D. Power

Answer: (C)

The ampere is used to quantify electric current—the rate at which electric charges flow through a conductor. An ampere means that one coulomb of charge passes a point each second, so current is the measure of how much charge moves per unit time. Because of that, current is the fundamental electrical quantity associated with the ampere.

Voltage, resistance, and power are described by other concepts and units. Voltage is the potential difference between two points and is measured in volts. Resistance is the opposition to current and is measured in ohms. Power is the rate of doing work or transferring energy and is measured in watts; it’s related to current and voltage by P = VI and to current and resistance by I = V/R. In aircraft systems, understanding current helps with sizing conductors, fuses, and circuit protection, while voltage, resistance, and power describe related but distinct aspects of the electrical system.