1

Chapter 6 Diodes and Their Applications

2

Objectives

Describe how the properties of a

semiconductor differ from those of a

conductor and an insulator.

Define donors and acceptors and discuss

their functions in creating P-type material

and N-type material.

Discuss the basic properties of a PN-

junction diode and sketch the form of the

terminal characteristic curve.

3

Objectives

Describe the ideal model and the constant voltage model for a junction diode and draw the equivalent circuit forms.

Analyze simple circuit forms containing diodes and determine when a diode is forward biased or reverse biased.

State the input-output properties of an ideal transformer in terms of the turns ratio.

4

Objectives

Draw the schematic diagram of a half-wave rectifier and analyze its operation.

Draw the schematic diagram of a full-wave rectifier with a center-tapped secondary and analyze its operation.

Draw the schematic diagram of a full-wave bridge rectifier and analyze its operation.

Describe the function of a rectifier filter and analyze the ripple level.

5

Objectives

Define peak inverse voltage and

determine its value for different rectifier

circuits.

Discuss the properties of different types of

diodes.

Draw the schematic diagram of a zener

regulator circuit and analyze its operation.

6

6-1 Semiconductor Concepts

Conductors, Insulators, and

Semiconductors

Electrons or Holes

Doping and Impurities (Donors or

Acceptors)

P-type and N-type Material

7

6-2 Junction Diode

Schematic Symbol

Applications

Terminal Characteristic

8

PN-junction diode and its schematic

symbol.

9

Ideal resistance and its terminal

characteristic.

10

Experiment used to determine

semiconductor diode terminal

characteristic.

11

Form of the terminal characteristic of a

semiconductor diode.

12

6-3 Diode Circuit Models

Ideal Diode Model

Constant Voltage Model

Other Models

Which Model is Appropriate?

Is a Diode Forward Biased or Reverse

Biased?

13

Ideal diode model and terminal

characteristic.

14

Constant voltage diode model and

terminal characteristic.

15

Circuit of Example 6-1.

16

Circuit of Example 6-2.

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6-4 Diode Rectifier Circuits

Why Convert AC to DC?

Half-Wave Rectifier Circuit (Unfiltered)

Full-Wave Rectifier Circuit (Unfiltered)

Full-Wave Rectifier Bridge

18

A half-wave rectifier without filtering and

the waveforms.

19

Schematic diagram of an unfiltered full-

wave rectifier with a center-tapped

transformer and the waveforms.

20

Conduction models for full-wave rectifier

with center tap for alternate half-cycles.

21

Schematic diagram of an unfiltered full-

wave bridge rectifier circuit.

22

Conduction models for bridge rectifier for

alternate half-cycles.

23

6-5 Rectifier Circuits with Filtering

Half-Wave Rectifier with Capacitor Filter

Full-Wave Rectifiers with Capacitor Filter

Ripple Analysis

Reverse Diode Voltage

More Complex Filter Circuits

Power Supplies with a Voltage Regulator

24

Schematic diagram of a basic half-wave

rectifier circuit with transformer and

capacitor filter.

25

Waveforms for half-wave rectifier with

transformer and filter.

26

Schematic diagram of a full-wave rectifier

circuit with transformer and capacitor

filter.

27

Schematic diagram of a full-wave bridge

rectifier circuit with capacitor filter.

28

Waveforms for full-wave rectifier without

and with filter.

29

Schematic diagram of a rectifier circuit

with voltage regulator.

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6-6 Survey of Other Diode Types

Zener Diode

Light Emitting Diode

Photodiode

Optocoupler

Schottky Diode

Varactor Diodes

31

Schematic symbols for various types of

diodes.

32

6-7 Zener Regulator Circuits

Qualitative Explanation

33

Typical zener regulator circuit.

34

Circuit of Example 6-8 with voltage and

current values labeled.

35

Circuit of Example 6-9 with voltage and

current values labeled.

36

Circuit of Example 6-10 with voltage and

current values labeled.