Which term describes a circuit that uses more than one phase of alternating current?

• A. Pole
• B. Phase difference
• C. Polyphase
• D. Potentiometer

Answer: (C)

Using more than one phase describes polyphase systems. In polyphase circuits you have multiple AC waveforms that are offset in time, such as three-phase power where the voltages are spaced apart (typically 120 degrees). This setup provides smoother power delivery, better efficiency, and more consistent torque for electric machines. The other terms refer to different ideas: pole relates to the number of magnetic poles in a machine or switch, not how many AC phases are used; phase difference is the offset between two existing phases, not the overall count of phases; and potentiometer is simply a variable resistor used to adjust voltage. So the term for a circuit using more than one AC phase is polyphase.