Two voltage waveforms are described as follows: Waveform A is a square wave that periodically alternates between +V₀ and -V₀ for equal time intervals. Waveform B is a square wave that periodically alternates between +V₀ and 0 for equal time intervals. Which of the following correctly identifies the alternating current (AC) waveform and gives its average value over one complete cycle?

Step-by-step solution

An alternating waveform must periodically reverse its polarity (i.e., it must cross the zero axis and take both positive and negative values). Waveform A alternates between +V₀ and -V₀ , meaning it reverses polarity. Therefore, it is an AC waveform. Waveform B alternates between +V₀ and 0 , meaning it never becomes negative. It is a pulsating DC waveform. For any symmetric AC waveform like Waveform A, the area under the curve for the positive half-cycle is exactly equal and opposite to the area under the curve for