Parul Institute of Engineering & Technology

Name of Unit : Diode And Its Applications___________

Topic : BRIDGE RECTIFIER_________________________

Name of Faculty : HUTESH BAVISKAR

INTRODUCTION

• One of most widely used electronic circuit to convert AC voltage to DC voltage.

• Since the rectifier circuit uses diodes to convert ac voltage to dc, its also called a converter circuit.

• All power that supply to a modern factory is alternating current, so it is important to have circuit that can convert the ac power to dc power since most solid-state device require a source of dc power to operate.

TYPES OF RECTIFIERS

Centre-tape full-wave rec.

Full-waveBridge rec.

SINGLE PHASE RECTIFIER

• The transformer feeding a resistor as its load with a rectifier inserted in the circuit.

• The rectifier will conduct each time its anode is positive with respect to its cathode.

• So when the end of the secondary winding shown + is positive, the diode acts as a short-circuit and the + appears across the load.

• Current flows around the secondary circuit for the time that the diode is conducting.

• The waveform appearing across the load is shown in red on the graph.

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• One-half cycle of the AC from the transformer is conducted by the rectifier, one half cycle is stopped. This is pulsating DC - half-wave rectified .

• Its is important to be able to calculate the amount of DC average voltage that available at the load.

Sub: B.E. Topic: BRIDGE RECTIFIER

TWO DIODE FULL WAVE SINGLE- PHASERECTIFIER

Sub: B.E. Topic: BRIDGE RECTIFIER

• This is two half-wave rectifiers combined - it uses a center-tapped secondary winding and one additional diode.

• Each side of the centre-tap has the same number of turns as our previous example - and each "works" for half the cycle as our half-wave rectifier did.

• The "top half" of the secondary works with one diode like the half-wave circuit we have just considered.

• When the polarity of the secondary changes, the upper diode shuts off and the lower diode conducts.

Sub: B.E. Topic: BRIDGE RECTIFIER

FOUR DIODE FULL WAVE BRIDGE RECTIFIER

Topic: BRIDGE RECTIFIER

FULL WAVE RECTIFIER• Full-wave bridge Rectifier:

• Circuit Diagram with waveforms:

Topic: BRIDGE RECTIFIER

• This uses one single winding as the secondary and four diodes - two are conducting at any one time.

• The operation is simple: Parallel-side diodes conduct at the same time. Note that the two + points are connected by a diode - same as in the two previous cases. The other end of the load returns to the transformer via the other parallel diode. When the polarity changes, the other two diodes conduct.

• The output waveform is the same as the full-wave rectifier example shown before.

Topic: BRIDGE RECTIFIER

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• The main advantage? A simpler transformer - no centre-tap and no extra winding. Diodes can be small and cheap. A bridge rectifier can be purchased as a "block" with four wire connections.

Topic: BRIDGE RECTIFIER