With the help of a labelled circuit diagram, explain the working of a full-wave rectifier. Draw its input and output waveforms.

1. 1 · Define rectification. A rectifier changes AC into one-way (DC) voltage using the one-way conduction of diodes.
2. 2 · Draw the circuit. [Circuit: centre-tap transformer with ends A, B and centre tap C; D1 from A and D2 from B joined at one point; RL from that point to C; current arrow through RL]
3. 3 · Explain the first half cycle. A is positive with respect to C: D1 is forward biased and conducts; D2 is reverse biased.
4. 4 · Explain the second half cycle. B is positive with respect to C: D2 conducts; D1 is reverse biased. Current through RL is in the same direction as before.
5. 5 · Draw the waveforms. [Waveforms: input sine wave; output from D1 and D2 in alternate halves; combined output of positive humps with no gaps]
6. 6 · State the output frequency and smoothing. Output frequency is twice the input (100 Hz for 50 Hz). A capacitor across RL smooths the ripple.
7. 7 · Real life. Every phone charger begins with a rectifier and a smoothing capacitor.
8. 8 · Close in one line. So, the two diodes take turns, and the load gets one-way current in both halves of every cycle.

Scoring tip: Line up the input and output waveforms on the same time axis, and mark which diode conducts in each half.