An AC circuit is described as

An AC circuit is described as

• A. A circuit that contains a capacitor
• B. A circuit that uses a single resistor
• C. A circuit that carries direct current, or current that flows in only one direction
• D. A circuit that carries alternating current, or current that periodically reverses direction

Answer: (D)

AC means the current and voltage in the circuit vary with time and reverse direction periodically. In practical terms, the supply alternates back and forth, so electrons flow first in one direction and then the opposite way at the line frequency (such as 50 or 60 Hz). This alternating flow is what defines an AC circuit, unlike direct current, which flows in one direction only. The presence of a capacitor or a resistor doesn't by itself determine AC versus DC—the key is the source and the resulting current behavior. A circuit with components like a resistor or capacitor can be driven by an AC source and operate as an AC circuit, while a circuit fed by a DC source yields DC. So an AC circuit is described as one that carries alternating current, or current that periodically reverses direction.

AC means the current and voltage in the circuit vary with time and reverse direction periodically. In practical terms, the supply alternates back and forth, so electrons flow first in one direction and then the opposite way at the line frequency (such as 50 or 60 Hz). This alternating flow is what defines an AC circuit, unlike direct current, which flows in one direction only. The presence of a capacitor or a resistor doesn't by itself determine AC versus DC—the key is the source and the resulting current behavior. A circuit with components like a resistor or capacitor can be driven by an AC source and operate as an AC circuit, while a circuit fed by a DC source yields DC. So an AC circuit is described as one that carries alternating current, or current that periodically reverses direction.