This document discusses diodes and their applications. It begins with an introduction to diodes, including what a diode is, the P-N junction, and diode characteristics when forward and reverse biased. It then covers types of diodes like LEDs, Zener diodes, and more. Applications discussed include logic gates, temperature measurement, and power conversion. The document focuses on rectifiers, explaining half-wave and full-wave rectification and how diodes are used to convert AC to DC in power supplies. Circuit diagrams are provided to illustrate the principles and components of half-wave and full-wave rectifiers, including the addition of a capacitor filter.

1. Presented by: - Mohamed Fdaili
- Amina Zakani
- Chaimaa Oukrati
Framed by: Mr.A.Neddami

2. 2
Conclusion
Diode applications
Types of diodes
Diode characteristics
What is a diode ?
P-N Junction
Introduction

3. SEMICONDUCTOR
3

4. 4
When P-type and N-type materials are joined , this forms a
P-N junction.
Impurity
atoms
(fixed)
p - type
material
n - type
material
Holes
(mobile
carriers)
Electrons
(mobile
carriers)
Electrons
(negative charge
carriers)
Holes
(positive charge
carriers)
Depletion
layer

5. 5
 When forward biased, a diode acts as a conductor and current flows.
 When reverse biased, a diode acts as an insulator and no current flows.

6. 6
It is an electronic device that ideally conducts in
only one direction.
Actual Features : Electrical Symbol :

7.  Ideal Diode Model (without threshold )
7

8.  Ideal Diode Model ( with threshold)
8

9.  Real diode ( with threshold and resistance)
9

10. 10
s
I I
qV
kT
where
I diode current with reversebias
q coulomb the electronic ch e
k
eV
K
Boltzmann s cons t






 







 
 


0
0
19
5
1
1602 10
862 10
exp ,
. , arg
. , ' tan

11. 11
• Light Emitting Diode (LED)
• Avalanche Diode.
• Laser Diode.
• Schottky Diode.
• Photo Diode.
• Varicap Diode or Varactor Diode.
• Zener Diode.
• Rectifier Diode.

12. Logic gates :
Diodes can be combined with other components to
construct AND and OR logic gates. This is referred to
as diode logic.
Temperature measurement :
A diode can be used as a temperature measuring
device, since the forward voltage drop across the diode
depends on temperature, as in a Silicon band gap
temperature sensor.
Power conversion :
Rectifiers are constructed from diodes, where they are
used to convert alternating current (AC) electricity
into direct current (DC).
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13. Principle of rectifying
13
Rectifiers

14. Two types of rectification :
a) Half-wave rectifier
The simplest rectifier circuit is called the ‘Half-Wave’ rectifier
as it only converts one half cycle.
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15. The supply voltage is given by: Vin =Vm sinΩt ;Ω=2πf = 2 π /T
The waveforms for source voltage Vin and output voltage Vout are :
15

16.  Output DC voltage :
Vave =Vm/ Iave=Vave/R
16

17. b) Full-wave rectifier
 Two diodes :
The full wave rectifier consists of two diodes and a resister as
shown in Figure:
17

18. DC voltage output:
Vave =2Vm/ Iave=Vave/R
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19.  Four diodes :
positive alternation
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20.  Output DC voltage: Vave =2Vm/ 20
Negative alternation

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with capacitor filter :

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