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a Bridge Rectifier Work

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•Rectifier Circuits : Rectifiers convert ac into dc Bridge Rectifier

Looks like a Wheatstone bridge. Does not require a enter tapped transformer.

Requires 2 additional diodes and voltage drop is double.

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Diode Bridge Rectifier Basics

• A diode bridge rectifier is a device for converting AC, or alternating current electricity into DC, or direct current. AC electricity goes from positive to negative constantly, whereas DC always flows in the same direction. AC electricity is more efficient to transmit and easier to convert into different voltages, so power is transmitted from the station to your house as AC. However, most appliances need DC current to run. A diode bridge rectifier is the most common type of power supply used to provide this current.

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120/25VTransformer

120VVariac

Important − never connect a DBR directly to 120Vac or directly to a variac. Use a 120/25V

transformer. Otherwise, you may overvoltage the electrolytic capacitor

Diode Bridge Rectifier(DBR)

+

–

+≈ 28Vac rms

–

1

4

3

2

Equivalent DC load resistance RL

+≈ 28√2Vdc ≈ 40Vdc−

Iac

Idc

Be extra careful that you observe the polarity markings on the electrolytic capacitor

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AC and DC Waveforms for a Resistive Load

Vac

-40

-20

0

20

40

0.00 8.33 16.67 25.00 33.33

Milliseconds

Volts

With a resistive load, the ac and dc current waveforms have the same waveshapes as Vac and Vdc shown above

+ Vac > 0

–

1

2

+ Vdc

– – Vac < 0

+

4

3 + Vdc

–

Vdc

-40

-20

0

20

40

0.00 8.33 16.67 25.00 33.33

MillisecondsVo

lts

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