21.2 Rectification and smoothing

Half-wave rectification passes one polarity half-cycle; full-wave rectification flips both half-cycles to the same load polarity.

Read the output graph: half-wave has gaps each alternate half-cycle, while full-wave pulses occur twice per input cycle and have higher ripple frequency.

A bridge rectifier uses four diodes to produce full-wave output without a centre-tapped transformer.

Rectification does not by itself make perfectly steady DC; smoothing capacitors reduce ripple after the diode stage.

A diode conducts mainly in forward bias and blocks reverse bias, so one diode passes only one half-cycle of an AC input.

Read diode orientation and output polarity, then identify the gaps in the load voltage waveform.

A positive half-wave output has pulses separated by zero-voltage intervals during the negative input half-cycle.

A diode does not convert AC directly into smooth DC; the output is pulsating and needs smoothing.

In a bridge rectifier, two diodes conduct on each half-cycle so current through the load keeps the same direction.

Trace the conducting pair for positive and negative input halves, then identify the doubled ripple frequency.

The bridge produces full-wave pulsating output without a centre-tapped transformer, though two diode drops appear in each conducting path.

All four diodes do not conduct simultaneously in the ideal bridge, and rectification alone does not remove ripple.

A capacitor across a rectifier load charges when input exceeds its voltage and discharges through the load between peaks, reducing ripple.

Larger C or lighter load slows discharge; check the polarity and allow for diode conduction only near peaks.

A full-wave rectifier with a reservoir capacitor has smaller ripple intervals than a half-wave circuit at the same input frequency.

Smoothing does not make voltage perfectly constant, and an infinitely large capacitor would create unrealistic charging currents.