What continually changes in amplitude and reverses direction?

What continually changes in amplitude and reverses direction?

• A. Direct current
• B. Pulsed current
• C. Impulse current
• D. Alternating Current (AC)

Answer: (D)

Current that continually changes in amplitude and reverses direction is Alternating Current. In AC, the flow of electrons oscillates back and forth, so the current rises and falls in magnitude while periodically changing sign—positive in one half-cycle and negative in the next. This reversal happens regularly, following the waveform, commonly a smooth sine wave, and the peak value is the amplitude of the current. Direct current stays in one direction with a constant (or near-constant) magnitude, so it does not reverse. Pulsed current occurs as bursts in one direction with varying amplitude but without continual reversal. Impulse current is a short, single spike rather than a continuous reversing waveform. So the defining behavior—changing magnitude with direction reversal—belongs to alternating current.

Current that continually changes in amplitude and reverses direction is Alternating Current. In AC, the flow of electrons oscillates back and forth, so the current rises and falls in magnitude while periodically changing sign—positive in one half-cycle and negative in the next. This reversal happens regularly, following the waveform, commonly a smooth sine wave, and the peak value is the amplitude of the current. Direct current stays in one direction with a constant (or near-constant) magnitude, so it does not reverse. Pulsed current occurs as bursts in one direction with varying amplitude but without continual reversal. Impulse current is a short, single spike rather than a continuous reversing waveform. So the defining behavior—changing magnitude with direction reversal—belongs to alternating current.