Rectification
Physics: Cambridge International A Level, topic 13.2.4
Rectification
Rectification is the process of converting an alternating current into a direct current.
Half-wave rectification
- A rectifier is a component that turns an alternating current into a direct current (one direction.
- Diodes act as rectifiers as they block the alternating current when it changes direction.
- This is known as a half-wave rectification, as it only allows half of the wave to pass through.
Full-wave rectification
- Full-wave rectification involves reversing the direction of the parts of the wave that would be cut out by half-wave rectification.
- This produces an output that more closely resembles a direct current than for half-wave rectification.
- To make the output current more like a direct curent, we can use a process called smoothing.
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Smoothing
- Smoothing is achieved by using a capacitor.
- The alternating current charges up the capacitor, which periodically discharges when the current reaches its peak.
- The discharge of the capacity 'slows down' the decrease of the current, smoothing out the bumps.
- The lower the load resistance of the circuit, the higher the capacitance of the capacitor.
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Bridge rectifier
- A bridge rectifier is an array of four diodes arranged in such a way that performs a full-wave rectification on an alternating current input.
- When the alternating current is positive, the current travels from the input terminal and passes through one of the diodes, producing a direct current at the positive output terminal.
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Bridge rectifier cont.
- When the alternating current switches direction, the current travels from the other input terminal, through one diode, maintaining the direct current at the positive output terminal.
Test yourself on Rectification
Which of the following circuit components is used to perform smoothing on a rectified current?