Which statement correctly differentiates AC coupling from DC coupling?

Which statement correctly differentiates AC coupling from DC coupling?

• A. AC - direct current; DC - alternating current
• B. AC - alternating current; DC - direct current and does not change
• C. AC - direct current; DC - direct current and stays the same
• D. AC - alternating current; DC - direct current and changes sign

Answer: (B)

AC coupling and DC coupling hinge on what the signals actually are and how they behave. AC means alternating current, which periodically reverses direction. DC means direct current, which maintains a constant polarity over time. The statement that correctly differentiates them is that AC is alternating current and DC is direct current and does not change. This captures both the terminology and the behavior: DC stays steady, while AC varies with time. The other options either swap the meanings or imply that DC changes sign, which isn’t the case.

AC coupling and DC coupling hinge on what the signals actually are and how they behave. AC means alternating current, which periodically reverses direction. DC means direct current, which maintains a constant polarity over time. The statement that correctly differentiates them is that AC is alternating current and DC is direct current and does not change. This captures both the terminology and the behavior: DC stays steady, while AC varies with time. The other options either swap the meanings or imply that DC changes sign, which isn’t the case.