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it was my first presentation in technical english
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Analog Electronic : Diodes
Presented by: - Mohamed Fdaili
- Amina Zakani
- Chaimaa Oukrati
Framed by: Mr.A.Neddami
2
Outline
Conclusion
Diode applications
Types of diodes
Diode characteristics
What is a diode ?
P-N Junction
Introduction
3
SEMICONDUCTOR
N-TYPE
P-TYPE
Introduction
4
The P-N junctionWhen 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
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Forward and reverse bias
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.
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what is a diode ?
It is an electronic device that ideally conducts in only one direction.
Actual Features :
Electrical Symbol :
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Ideal Diode Model (without threshold )
Diode Characteristics
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Ideal Diode Model ( with threshold)
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Real diode ( with threshold and resistance)
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The Ideal Diode Equation
s
I IqV
kT
where
I diode current with reverse bias
q coulomb the electronic ch e
keV
KBoltzmann s cons t
0
0
19
5
1
1602 10
8 62 10
exp ,
. , arg
. , ' tan
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Types of diodes• Light Emitting Diode (LED)
• Avalanche Diode.
• Laser Diode.
• Schottky Diode.
• Photo Diode.
• Varicap Diode or Varactor Diode.
• Zener Diode.
• Rectifier Diode.
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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).
Diode Applications
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Principle of rectifying
Rectifiers
The use of diodes as Rectifiers
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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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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 :
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Output DC voltage :
Vave =Vm/ Iave=Vave/R
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b) Full-wave rectifier Two diodes : The full wave rectifier consists of two diodes and a resister as
shown in Figure:
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DC voltage output:
Vave =2Vm/ Iave=Vave/R
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Four diodes :
positive alternation
20 Output DC voltage: Vave =2Vm/
Negative alternation
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with capacitor filter :
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Dc power supply circuit
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conclusion
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That's All.Thank You for Your Attention