Half-wave Rectifier

NCERT explains that a half-wave rectifier uses a single diode in series with the load. During the half cycle when the diode is forward biased, it conducts and the input voltage appears across the load, but during the opposite half cycle the diode is reverse biased and blocks current, so no output appears. As a result only one half of each alternating cycle is delivered to the load, giving a pulsating unidirectional output with gaps. The option describing both halves as positive pulses is wrong because that is the behaviour of a full-wave rectifier using two or more diodes. The option describing a perfectly steady constant voltage is wrong because the raw rectified output is pulsating and requires a filter capacitor to smooth it. The option describing an alternating output identical to the input is wrong because rectification specifically removes one polarity. As stated in NCERT Class 12, Chapter 14, a half-wave rectifier conducts during only one half of the cycle. A consistency check confirms the output has the same frequency as the input, since one pulse appears per input cycle in half-wave operation.