Full Wave Rectifier
A half-wave rectifier is a basic circuit used to convert AC (Alternating Current) into DC (Direct Current). It allows only one half-cycle (positive or negative) of AC to pass while blocking the other half.
Applications:
Used in low-power DC supplies
Signal demodulation in radio receivers
Voltage multiplication circuits
A full-wave rectifier is an electronic circuit that converts an alternating current (AC) input into a direct current (DC) output. Unlike a half-wave rectifier, which utilizes only one half-cycle of the AC input, a full-wave rectifier uses both positive and negative half-cycles, making it more efficient.
Types of Full-Wave Rectifiers:
Center-Tapped Full-Wave Rectifier
Bridge Full-Wave Rectifier
Both configurations have the same working principle but differ in design.
2. Circuit Diagram & Working Principle
(A) Center-Tapped Full-Wave Rectifier
Circuit Components:
AC Transformer: Provides step-down AC voltage.
Center-Tapped Transformer: The secondary winding has a middle tap acting as a reference ground.
Two Diodes (D₁ & D₂): Conduct alternately in each half-cycle.
Load Resistor (RLR_L): The rectified DC output is taken across this resistor.
Circuit Diagram:
Working of Center-Tapped Full-Wave Rectifier
1. Positive Half-Cycle:
The upper half of the secondary winding gets positive voltage, and the lower half gets negative voltage.
Diode D1D_1 conducts (forward-biased), allowing current to flow through RLR_L.
Diode D2D_2 is reverse-biased and does not conduct.
The output voltage follows the positive half-cycle of AC.
2. Negative Half-Cycle:
The upper half of the secondary winding becomes negative, and the lower half becomes positive.
Diode D2D_2 conducts, while D1D_1 is reverse-biased.
Current flows through RLR_L in the same direction as before.
The output voltage follows the positive half-cycle, making it continuous DC.
🔷 Final Output: The rectifier inverts the negative half-cycle into positive, producing continuous pulsating DC.
(B) Bridge Full-Wave Rectifier
Circuit Components:
Four Diodes (D1,D2,D3,D4D_1, D_2, D_3, D_4): Form a bridge circuit.
Transformer: Steps down AC voltage.
Load Resistor (RLR_L): DC output is taken across this resistor.
Circuit Diagram:
Working of Bridge Full-Wave Rectifier
Uses four diodes arranged in a bridge configuration.
Eliminates the need for a center-tapped transformer.
✔ Advantage: Works with a normal transformer, reducing cost.
3. Output Waveform
The output waveform of a full-wave rectifier is a pulsating DC.
Graphical Representation:
Input AC: ~~~~~~~~|~~~~~~~~|~~~~~~~~|~~~~~~~~|~~~~
(Sine Wave)
Output DC: __/\/\/\/\/\/\__/\/\/\/\/\/\__/\/\/\/\/\/\__
Both half-cycles are converted to positive.
Higher DC output compared to half-wave rectifier.
4. Mathematical Derivation of Important Expressions
5. Advantages and Disadvantages
Advantages:
✔ Higher Efficiency (~81.2%)
✔ Lower Ripple Factor (~0.48)
✔ Uses both halves of AC signal
Disadvantages:
❌ Needs more components (2 or 4 diodes, transformer)
❌ More complex design than half-wave rectifier
6. Applications of Full-Wave Rectifier
✅ Power Supplies – Converts AC to smooth DC.
✅ Battery Chargers – Used in charging circuits.
✅ Radio and TV Receivers – For demodulation.
7. Conclusion
A full-wave rectifier is much more efficient than a half-wave rectifier. It converts both AC half-cycles into DC and provides a higher DC output voltage with less ripple.
