Physics · Semiconductor Electronics : Materials, Devices And Simple Circuits · NEET
A plain rectifier gives pulsating DC, not smooth DC. The current always flows in one direction (so it is DC), but its value rises and falls with each cycle. To make it smoother we add a filter capacitor, which reduces the ac ripple. Only after filtering does it look close to steady DC.
A p-n junction diode conducts only when forward biased and blocks current when reverse biased. AC keeps changing direction, so during one half the diode is forward biased (current passes) and during the other half it is reverse biased (current blocked). This one-way action is exactly what converts AC into one-directional DC.
AC input changes direction many times per second, so its average value over a full cycle is zero. The DC output flows in only one direction, so it has a non-zero average value. The rectifier does not create energy; it just removes (or flips) the reverse-direction part of the wave.
No. The diode is the essential part that provides one-way conduction. Without a diode (or a similar one-way device), there is nothing to stop the reverse half of the AC, so the output would still be AC. The transformer only changes voltage level, and the capacitor only smooths - neither can rectify on its own.
No, it is not constant. In half-wave rectification the output appears only during one half of each cycle; in full-wave rectification it appears during both halves but still rises and falls. It is unidirectional but not flat. A capacitor filter is needed to make it nearly constant.
A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components removes the ac ripple from the rectified output?
In half wave rectification, if the input frequency is 60 Hz, then the output frequency would be:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It is an electronic circuit that turns AC (current that keeps reversing) into DC (current that flows in one direction only), using diodes as one-way gates.
Half-wave rectifier (uses one diode, rectifies only one half of each cycle) and full-wave rectifier (uses two or more diodes, rectifies both halves). Full-wave is more efficient and easier to smooth.
Most electronic devices - phones, laptops, LEDs, ICs - need steady DC to work, but the supply from the mains is AC. A rectifier plus filter provides the DC these devices need.
The capacitor removes the ripple. The diode only makes the current one-directional (pulsating DC); the capacitor filter smooths that pulsating DC into nearly steady DC.
No. A transformer only steps voltage up or down and still gives AC. A rectifier converts AC to DC. In a real power supply both are used together.
