Based on the understanding operations of rectifies answer the questions Diodes can be used for rectifying on ac voltage (restricting the ac voltage to one direction) with the help of a capacitor or a suitable filter, a dc voltage ca be obtained.
Input and output voltage signal for a device \( X \) are shown below. Identify \( X \).
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Half wave rectifier
The input is a complete sine wave. The output keeps only the positive half-cycles and is zero during the negative half-cycles, leaving a gap after each pulse. Passing one half-cycle and blocking the other is the action of a half wave rectifier.
Option (1) Zener diode — Incorrect. A Zener diode is used as a voltage regulator: it holds the voltage across it nearly constant; it does not simply remove alternate half-cycles.
Option (2) Full wave rectifier — Incorrect. A full wave rectifier turns the negative half-cycles into positive pulses too, so its output has a pulse in every half-cycle with no gaps.
Option (3) Half wave rectifier — Correct. Only one half of each cycle appears at the output, with gaps in between.
Option (4) Light emitting diode — Incorrect. An LED converts electrical energy into light; it is not a waveform-shaping device.
NCERT (2026-27):
Application of Junction Diode as a Rectifier – “… If an alternating voltage is applied across a diode in series with a load, a pulsating voltage will appear across the load only during the half cycles of the ac input during which the diode is forward biased. Such rectifier circuit, as shown in Fig. 14.18, is called a half-wave rectifier.”