Which current reverses direction periodically?

Which current reverses direction periodically?

• A. Direct Current (DC)
• B. Pulsating DC
• C. Alternating Current (AC)
• D. DC with ripple

Answer: (C)

Current direction reverses periodically when the driving voltage changes polarity over time. In alternating current, the voltage varies and crosses zero, becoming opposite in sign and then repeating, so the current flows in one direction during the positive half-cycle and in the opposite direction during the negative half-cycle. The rate of reversal is the frequency of the supply (for household power, typically 50 or 60 times per second). Direct current keeps the same polarity, so the current travels in one direction continuously. Pulsating DC and DC with ripple change magnitude but not the direction, so they do not reverse direction. That makes alternating current the one that reverses direction periodically.

Current direction reverses periodically when the driving voltage changes polarity over time. In alternating current, the voltage varies and crosses zero, becoming opposite in sign and then repeating, so the current flows in one direction during the positive half-cycle and in the opposite direction during the negative half-cycle. The rate of reversal is the frequency of the supply (for household power, typically 50 or 60 times per second).

Direct current keeps the same polarity, so the current travels in one direction continuously. Pulsating DC and DC with ripple change magnitude but not the direction, so they do not reverse direction. That makes alternating current the one that reverses direction periodically.