What is Full Wave Rectifier?
Full wave rectifier consists of semiconductor devices which converts both positive and negative cycle of the input alternating current(AC) into pulsating direct current(DC). The drawback of the Half wave rectifier is overcome by Full wave rectifier.
- Center tapped two diode full wave rectifier
- Bridge rectifier
Center tapped two diode Full wave rectifier:
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| Center tapped two diode full wave rectifier |
In this method a center tapped transformer and two diodes are used. One diode is used for positive cycle of the alternating current and another diode is used for the negative cycle of the input current. So the full wave rectifier is like back to back two half wave rectifier.
Working of Center tapped two diode Full wave rectifier:
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| Working of full wave rectifier |
When the positive cycle of the input alternating current is applied to the transformer, diode D1 is forward biased and D2 is reverse biased.
So the D1 acts as a closed circuit and D2 acts like a open circuit. So the positive half cycle of the alternating current is converted into pulsating DC output.
When the negative cycle of the input voltage is applied, D1 is reverse biased and acts as an open circuit and D2 is forward biased and acts as a closed circuit.
Thus the negative half cycle of the alternating input voltage is converted into pulsating DC output.
Center tapped Full wave rectifier with soothing capacitor:
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| Full wave rectifier with capacitor filter |
The output of the full wave rectifier consists of ripples or variations. So a capacitor filter is used.
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| Working of full wave rectifier with capacitor filter |
Initially the capacitor is uncharged. Then slowly capacitor charges and attains maximum when the input voltage reaches its maximum.
When the input voltage drops the capacitor starts discharging very slowly and it does not discharges completely, again it starts charging.
So by using soothing capacitor, unnecessary ripples can be removed from the generated output. Thus pure DC output is obtained.
Full wave rectifier calculations:
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| Full wave rectifier calculations |
Advantages:
• Ripple
factor is less than halfwave rectifier.
• Rectification
efficiency is higher.
• Both
positive and negative cycle of AC waveform are rectified.
• Transformer
utilization factor is high.
• Ripple
factor is less.
Disadvantages:
• Manufacturing
cost is high
• It
requires more diodes
• Peak
inverse voltage of the diodes should be high
Applications:
• To
modulate the amplitude in the radio signal
• It
is used in power supply unit
• Full
wave rectifiers are used to power up motors
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