WELCOME TO MY
PRESENTATION
PRESENTED BY
Name: Kawsar Ahmed
ID: 12105297
Program: BSEEE
PRESENTATION TOPIC:
Bipolar Junction
Transistors
Bipolar Junction Transistors
• The transistor is a three-layer semiconductor
device consisting of either two n- and one p-...
Bipolar Junction Transistors
In each transistor following points to be noted-
i) There are two junction, so transistor can...
Naming of Transistor Terminals
• Transistor has three section of doped
semiconductor.
• The section one side is called “em...
Naming of Transistor Terminals
1) Emitter:
 The section of one side that supplies
carriers is called emitter.
 Emitter i...
Naming of Transistor Terminals
2) Collector:
The section on the other side that collects
carrier is called collector.
 T...
Naming of Transistor Terminals
3) Base:
The middle section which forms two pn
junction between emitter and collector is
c...
Some important factors to be
remembered-
• The transistor has three region named emitter,
base and collector.
• The Base i...
Some important factors to be
remembered-
• The junction between emitter and base is called
emitter-base junction(emitter d...
Transistor Operation
1) Working of npn transistor:
 Forward bias Is
applied to emitter-
base junction and
reverse bias is...
Transistor Operation
1) Working of npn transistor:
 As this electrons flow toward p-type base,
they try to recombine with...
Transistor Operation
2) Working of pnp transistor:
 Forward bias is
applied to emitter-
base junction and
reverse bias is...
Transistor Operation
2) Working of pnp transistor:
 As this holes flow toward n-type base, they
try to recombine with ele...
Transistor Symbol
Transistor Operating Modes
• Active Mode
 Base- Emitter junction is forward and Base-
Collector junction is reverse biase...
Transistor Connection
• Transistor can be connected in a circuit in
following three ways-
1) Common Base
2) Common Emitter...
Common Base Connection
• The common-base terminology is derived
from the fact that the base is common to both
the input an...
Common Base Connection
• Current amplification factor ( ) :
The ratio of change in collector current to the
change in emit...
Expression for Collector Current
Total emitter current does not reach the collector
terminal, because a small portion of ...
Expression for Collector Current
Characteristics of common base
configuration
• Input Characteristics:
VBE vs IE characteristics is
called input
character...
Characteristics of common base
configuration
Output Characteristics:
VBc vs Ic
characteristics is called
output character...
Input and Output Resistance of
common base conf.
• Input Resistance: The ratio of change in
emitter-base voltage to the ch...
Common Emitter Connection
• The common-emitter terminology is derived from
the fact that the emitter is common to both the...
Common Emitter Connection
• Base Current amplification factor ( ) :
• In common emitter connection input current is base
c...
Relation Between and 
Expression for Collector Current
Characteristics of common emitter
configuration
• Input Characteristics: VBE vs IB characteristics is
called input
charac...
Characteristics of common emitter
configuration
• Output Characteristics:
VCE vs Ic
characteristics is called
output char...
Input and Output Resistance of
common emitter conf.
• Input Resistance: The ratio of change in
emitter-base voltage to the...
Common Collector Configuration
• The common-collector terminology is derived from
the fact that the collector is common to...
Common Collector Configuration
• Current amplification factor ( ) :
• In common emitter connection input current is base
c...
Relation Between and 
Expression for Collector Current
Comparison of Transistor Connection
Transistor as an amplifier in CE conf.
• Figure shows CE amplifier for npn transistor.
• Battery VBB is connected with bas...
Transistor as an amplifier in CE conf.
• During positive half cycle input ac will keep the emitter-
base junction more for...
Transistor Load line analysis
• In transistor circuit analysis it is necessary to
determine collector current for various ...
Transistor Load line analysis
Consider common emitter
npn transistor ckt shown in
figure.
There is no input signal.
 Ap...
Transistor Load line analysis
Operating Point
It is called operating point because variation of IC
takes place about this point.
 It is also called qu...
ANY QUESTION?
THANKS TO ALL
for stay with me
of 45

Presentation on bipolar junction transistor

Presentation on bipolar junction transistor
Published on: Mar 4, 2016
Published in: Engineering      
Source: www.slideshare.net


Transcripts - Presentation on bipolar junction transistor

  • 1. WELCOME TO MY PRESENTATION
  • 2. PRESENTED BY Name: Kawsar Ahmed ID: 12105297 Program: BSEEE
  • 3. PRESENTATION TOPIC: Bipolar Junction Transistors
  • 4. Bipolar Junction Transistors • The transistor is a three-layer semiconductor device consisting of either two n- and one p- type layers of material or two p- and one n- type layers of material. • The former is called an npn transistor, while the latter is called a pnp transistor • So, there are two types of BJT- i) pnp transistor ii) npn transistor
  • 5. Bipolar Junction Transistors In each transistor following points to be noted- i) There are two junction, so transistor can be considered as two diode connected back to back. ii) There are three terminals. iii)The middle section is thin than other.
  • 6. Naming of Transistor Terminals • Transistor has three section of doped semiconductor. • The section one side is called “emitter” and the opposite side is called “collector”. • The middle section is called “base”. Transistor symbol
  • 7. Naming of Transistor Terminals 1) Emitter:  The section of one side that supplies carriers is called emitter.  Emitter is always forward biased wr to base so it can supply carrier.  For “npn transistor” emitter supply holes to its junction.  For “pnp transistor” emitter supply electrons to its junction.
  • 8. Naming of Transistor Terminals 2) Collector: The section on the other side that collects carrier is called collector.  The collector is always reversed biased wr to base. For “npn transistor” collector receives holes to its junction.  For “pnp transistor” collector receives electrons to its junction.
  • 9. Naming of Transistor Terminals 3) Base: The middle section which forms two pn junction between emitter and collector is called Base.
  • 10. Some important factors to be remembered- • The transistor has three region named emitter, base and collector. • The Base is much thinner than other region. • Emitter is heavily doped so it can inject large amount of carriers into the base. • Base is lightly doped so it can pass most of the carrier to the collector. • Collector is moderately doped.
  • 11. Some important factors to be remembered- • The junction between emitter and base is called emitter-base junction(emitter diode) and junction between base and collector is called collector-base junction(collector diode). • The emitter diode is always forward biased and collector diode is reverse biased. • The resistance of emitter diode is very small(forward) and resistance of collector diode is high(reverse).
  • 12. Transistor Operation 1) Working of npn transistor:  Forward bias Is applied to emitter- base junction and reverse bias is applied to collector- base junction. The forward bias in the emitter-base junction causes electrons to move toward base. This constitute emitter current, IE
  • 13. Transistor Operation 1) Working of npn transistor:  As this electrons flow toward p-type base, they try to recombine with holes. As base is lightly doped only few electrons recombine with holes within the base. These recombined electrons constitute small base current. The remainder electrons crosses base and constitute collector current.
  • 14. Transistor Operation 2) Working of pnp transistor:  Forward bias is applied to emitter- base junction and reverse bias is applied to collector- base junction. The forward bias in the emitter-base junction causes holes to move toward base. This constitute emitter current, IE
  • 15. Transistor Operation 2) Working of pnp transistor:  As this holes flow toward n-type base, they try to recombine with electrons. As base is lightly doped only few holes recombine with electrons within the base. These recombined holes constitute small base current. The remainder holes crosses base and constitute collector current.
  • 16. Transistor Symbol
  • 17. Transistor Operating Modes • Active Mode  Base- Emitter junction is forward and Base- Collector junction is reverse biased. • Saturation Mode  Base- Emitter junction is forward and Base- Collector junction is forward biased. • Cut-off Mode  Both junctions are reverse biased.
  • 18. Transistor Connection • Transistor can be connected in a circuit in following three ways- 1) Common Base 2) Common Emitter 3) Common Collector
  • 19. Common Base Connection • The common-base terminology is derived from the fact that the base is common to both the input and output sides of the configuration. • First Figure shows common base npn configuration and second figure shows common base pnp configuration.
  • 20. Common Base Connection • Current amplification factor ( ) : The ratio of change in collector current to the change in emitter current at constant VCB is known as current amplification factor, .  Practical value of is less than unity, but in the range of 0.9 to 0.99   Vconstant CB E C at I I    
  • 21. Expression for Collector Current Total emitter current does not reach the collector terminal, because a small portion of it constitute base current. So, Also, collector diode is reverse biased, so very few minority carrier passes the collector-base junction which actually constitute leakage current, .  So, collector current constitute of portion of emitter current and leakage current . BCE III  CBOI  EI CBOI 0CBEC III  
  • 22. Expression for Collector Current
  • 23. Characteristics of common base configuration • Input Characteristics: VBE vs IE characteristics is called input characteristics.  IE increases rapidly with VBE . It means input resistance is very small.  IE almost independent of VCB.
  • 24. Characteristics of common base configuration Output Characteristics: VBc vs Ic characteristics is called output characteristics.  IC varies linearly with VBc ,only when VBc is very small.  As, VBc increases, IC becomes constant.
  • 25. Input and Output Resistance of common base conf. • Input Resistance: The ratio of change in emitter-base voltage to the change in emitter current is called Input Resistance. • Output Resistance: The ratio of change in collector-base voltage to the change in collector current is called Output Resistance. E BE i I V r    C BC I V r   0
  • 26. Common Emitter Connection • The common-emitter terminology is derived from the fact that the emitter is common to both the input and output sides of the configuration. • First Figure shows common emitter npn configuration and second figure shows common emitter pnp configuration.
  • 27. Common Emitter Connection • Base Current amplification factor ( ) : • In common emitter connection input current is base current and output current is collector current. • The ratio of change in collector current to the change in base current is known as base current amplification factor, . • Normally only 5% of emitter current flows to base, so amplification factor is greater than 20. Usually this range varies from 20 to 500.   B C I I   
  • 28. Relation Between and 
  • 29. Expression for Collector Current
  • 30. Characteristics of common emitter configuration • Input Characteristics: VBE vs IB characteristics is called input characteristics.  IB increases rapidly with VBE . It means input resistance is very small.  IE almost independent of VCE. IB is of the range of micro amps.
  • 31. Characteristics of common emitter configuration • Output Characteristics: VCE vs Ic characteristics is called output characteristics.  IC varies linearly with VCE ,only when VCE is very small.  As, VCE increases, IC becomes constant.
  • 32. Input and Output Resistance of common emitter conf. • Input Resistance: The ratio of change in emitter-base voltage to the change in base current is called Input Resistance. • Output Resistance: The ratio of change in collector-emitter voltage to the change in collector current is called Output Resistance. B BE i I V r    C CE I V r   0
  • 33. Common Collector Configuration • The common-collector terminology is derived from the fact that the collector is common to both the input and output sides of the configuration. • First Figure shows common collector npn configuration and second figure shows common collector pnp configuration.
  • 34. Common Collector Configuration • Current amplification factor ( ) : • In common emitter connection input current is base current and output current is emitter current. • The ratio of change in emitter current to the change in base current is known as current amplification factor in common collector configuration. • This circuit provides same gain as CE configuration as,  B E I I    CE II 
  • 35. Relation Between and 
  • 36. Expression for Collector Current
  • 37. Comparison of Transistor Connection
  • 38. Transistor as an amplifier in CE conf. • Figure shows CE amplifier for npn transistor. • Battery VBB is connected with base in-order to make base forward biased, regardless of input ac polarity. • Output is taken across Load R
  • 39. Transistor as an amplifier in CE conf. • During positive half cycle input ac will keep the emitter- base junction more forward biased. So, more carrier will be emitted by emitter, this huge current will flow through load and we will find output amplified signal. • During negative half cycle input ac will keep the emitter-base junction less forward biased. So, less carrier will be emitted by emitter. Hence collector current decreases. • This results in decreased output voltage (In opposite direction).
  • 40. Transistor Load line analysis • In transistor circuit analysis it is necessary to determine collector current for various VCE voltage. • One method is we can determine the collector current at any desired VCE voltage, from the output characteristics. • More conveniently we can use load line analysis to determine operating point.
  • 41. Transistor Load line analysis Consider common emitter npn transistor ckt shown in figure. There is no input signal.  Apply KVL in the output ckt-
  • 42. Transistor Load line analysis
  • 43. Operating Point It is called operating point because variation of IC takes place about this point.  It is also called quiescent point or Q-point.
  • 44. ANY QUESTION?
  • 45. THANKS TO ALL for stay with me

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