ALPHA BREATHING

Basics of Electrical & Electronics Engineering

UNIT – IV ELECTRONICS ENGINEERING

TOPIC: Half Wave & Full Wave Rectifier

Topics to be Discussed

Half wave rectifier & Full wave rectifier Ripple factor Efficiency Peak inverse voltage Transformer utilization factor Form factor Peak factor

Power Supply

• A group of circuits used to convert ac to dc.– Rectifier – Converts ac to pulsating dc.– Filter – Reduces variations in the rectifier output.– Voltage regulator – Maintains a constant dc output

voltage.

Rectifier

Rectifier is an electronic device used for converting ac voltage into dc voltage.

It utilizes PN junction diode Rectifiers are classified into two types

Half wave rectifierFull wave rectifier

Half Wave Rectifier

The Half wave rectifier is a circuit, which converts an ac voltage to dc voltage during only one half cycle only.

In the Half wave rectifier circuit shown above the transformer serves two purposes. It can be used to obtain the desired level of dc voltage (using step up or step down

transformers). It provides isolation from the power line.

Full Wave Rectifier

The full wave rectifier is a circuit, which converts an ac voltage to dc voltage during both positive and negative half cycles.

TypesCentre tapped full wave rectifierBridge Rectifier

Centre tapped full wave rectifier

0 to π ---- D1 Forward biased

D2 Reverse biased

π to 2π ---- D2 Forward biased

D1 Reverse biased

Full wave Bridge rectifier

0 to π ---- D1, D2 Forward biased

D3, D4 Reverse biased

π to 2π ----D3, D4 Forward biased

D1, D2 Reverse biased

Ripple FactorRipple Factor

12 FFRF

Half Wave Rectifier

Derive Vdc & Idc

Derive Vrms

Half Wave Rectifier

Idc= Vdc/(rs+rf+RL)

Vdc = Vm/∏ - Idc (rs+rf )

Half Wave Rectifier

Full wave rectifier

Derive Vdc & Idc

Derive Vrms

Full wave rectifierRipple FactorRipple Factor

Idc= Vdc/(rs+rf+RL)

Vdc = 2Vm/∏ - Idc (rs+rf )

Half Wave RectifierEfficiency

Half Wave Rectifier

Full wave rectifierEfficiency, Form Factor & Peak Factor

414.12

2

m

m

rms

m

VV

V

VPF

Half Wave RectifierTransformer Utilization FactorTransformer Utilization Factor

Full wave rectifier TUF

TUF

Centre Tapped Full wave rectifier TUF =0.693

Full wave Bridge rectifier TUF =0.812

Peak Inverse Voltage Peak Inverse Voltage

Peak Inverse Voltage(PIV)Peak Inverse Voltage(PIV)

Maximum reverse voltage that a diode can withstand Maximum reverse voltage that a diode can withstand without destroying the junctionwithout destroying the junction

PIV = VPIV = Vm m for Half wave rectifier & Full wave bridge rectifierfor Half wave rectifier & Full wave bridge rectifier

PIV = 2VPIV = 2Vmm for centre tapped full wave rectifier for centre tapped full wave rectifier

ComparisonComparison

PUZZLE

• The ages of a father and son add up to 66. The

father's age is the son's age reversed. How old

could they be?

• ANS:

Father 51, son 15Father 42, son 24Father 60, son 06

PUZZLE

• Ram sat with his friends in the Chinnaswamy stadium in Bangalore to watch the 100 metres running race organized by the Asian athletics Association. Five rounds were run. After every round half the teams were eliminated. Finally, one team wins the game. How many teams participated in the race?

• ANS:32

• A grand father has 3 grand children. Age difference of two children among them is 3. Eldest child age is 3 times the youngest child’s age and the eldest child age is two year more than the sum of age of other two children. What is the age of the eldest child?

• ANS:15

READING

DRAW MINDMAP

SUMMARY

Moulting

(Drawing mind map on the board)

Mind Map

33

Half-wave rectifierFull-wave

Bridge rectifier

Ripple Factor 0.48

Rectifiers

PIV Vm

Peak Factor 2

TUF 0.287

Form Factor 1.57

PIV 2Vm

Centre Tapped Full-wave rectifier

PIV Vm

Ripple Factor 0.48

Ripple Factor 1.21

Peak Factor 1.414

Peak Factor 1.414

Form Factor 1.11

Form Factor 1.11

TUF 0.812

TUF 0.693

Moulting

(presentation within the group)