SlideShare a Scribd company logo
1 of 40
1
EST 130, Transistor Biasing
and Amplification
MEC
2
Contents
• Need for Biasing.
• Load Line and Q-Point.
• Transistor Operating Regions.
• Common Transistor Bias Circuits.
• Voltage Divider Bias.
• Common Emitter RC Coupled Amplifier.
• Use of Coupling Capacitors.
• Frequency Response.
3
Transistor Biasing
• Bias defined as a control voltage or
current.
• External dc supply voltage applied to
produce the desired collector current.
• Transistors biased correctly to produce the
desired circuit voltages and currents.
• Different biasing techniques - base bias,
voltage divider bias, emitter bias etc.
4
Transistor Operating Regions
Operating
Region
Emitter –
Base
Junction
Collector –
Base
Junction
Applications
Active
Region
Forward
Biased
Reverse
Biased
Amplifiers,
Oscillators
Saturation
Region
Forward
Biased
Forward
Biased Switches
(on/off)
Cut off
Region
Reverse
Biased
Reverse
Biased
Inverse Active
Region
Reverse
Biased
Forward
Biased
Not normally
used
5
Transistor Equations
• When transistor is in
saturation, Ic = Ic(sat)
and Vce ≈ 0V, Ic(sat) =
Vcc/Rc.
• Ic(sat) is the maximum
current that can flow
through Rc.
• When transistor is at
cut off, Ic ≈ 0, Vce =
Vce(off) = Vcc.
6
DC Load Line
• A graph that shows possible
combinations of IC and VCE
for a given amplifier.
• Endpoints of dc load line
labeled IC(sat) & VCE(off)
• IC(sat) - collector current IC
when transistor saturated.
• VCE(off) - collector- emitter
voltage with IC = 0 for cutoff.
Cut Off
Saturation
Active Region
Collector to Emitter Voltage
Collector
Current
7
Shift in Load Line with Collector
Resistance
When Rc↑ IC↓, load line shifts.
Vcc unchanged
8
Shift in Load Line with Supply
Voltage
Rc unchanged
9
Biasing Point
• Represents the collector to emitter voltage
and collector current of the transistor at
any instant.
• Biasing point to lie along the dc load line.
• Also called Quiescent Point (Q-point) or
the operating point.
• Q stands for quiescent currents and
voltages with no ac input signal applied.
10
Biasing Point
• Without ac signal applied to a transistor,
specific values of IC and VCE exist.
• IC and VCE values exist at a specific point
on the dc load line.
• Q Point to lie in active region for transistor
amplifiers.
• Q Point swings between saturation and cut
off for transistor switches.
11
Q-Point
• Amplifiers biased with Q point at or near
the center of the dc load line (active
region).
• ICQ = 1⁄2 IC(sat) and VCEQ = VCC /2.
Biasing for stability
of Q-Point.
12
Q-Point
• AC input signal adds to the bias voltage at
the base.
• Q Point swings up and down along the dc
load line when ac input signal applied to
the base.
• Swing to lie within the active region for
proper amplification.
• Q-Point preferably to be centered around
midpoint of the dc load line for amplifiers.
13
Q-Point
Transistor Output
Characteristics
14
Transistor in Saturation
 When a transistor is saturated:
• further increases in IB produce no further
increases in IC .
• the collector circuit no longer acts like a
current source since VCE ≈ 0 and the
collector-base junction of the transistor is
not properly reverse-biased.
• treat the collector-emitter region like a
short circuit.
15
Transistor at Cut Off
When the transistor is cut off:
• visualize the collector-emitter region as an
open circuit because IC ≈ 0.
• with zero collector current, ICRC voltage
drop is zero.
• resultant collector-emitter voltage VCE ≈
VCC.
16
Transistor in Active Region
 When a transistor is operating in the
active region:
• IC = βdc x IB.
• collector circuit acts as a current source
with high internal impedance.
17
Q-Point Swing in Active Region
Q-Point to be at the
centre of the load line
for maximum possible
output swing.
18
Q-Point Swing
Temperature variations
may affect Q-Point
Stability. Bias for thermal
stability of Q-Point.
19
Q-Point for Faithful Amplification
Output Voltage
Collector Current
Input
20
Q-Point Swing
Shaded portion removed,
distorts output waveform
when Q-Point is at cut
off.
21
Q-Point Swing
Shaded portion
removed, distorts
output waveform
when Q-Point is
in saturation.
22
Q-Point Swing
Q-Point Swings to Saturation Q-Point Swings to Cutoff
Clipped Off
Clipped Off
Output Output
23
Base Bias
• Simplest way to bias a
transistor.
• Base supply voltage
VBB to forward-bias the
base-emitter junction.
• Supply voltage Vcc
provides the reverse-
bias voltage required
for the collector-base
junction.
VB
E
24
Base Bias with Single Supply
A single supply Vcc provides both
base and collector bias
VBE
25
Base Bias
• Unstable Q point since collector current IC
and collector-emitter voltage, VCE affected
by changes in transistor beta (βdc) value.
• Q point might shift to a point located near
or at either cutoff or saturation when
transistor replaced.
• Beta varies with temperature.
• Change in the temperature can cause Q
point to shift.
26
Emitter Bias
• Solid Q point,
fluctuates very little
with temperature
variation & transistor
replacement.
• Emitter supply
voltage VEE forward-
biases the emitter-
base junction.
27
Voltage Divider Bias
• More stable and popular than other
biasing arrangements.
• A potential divider provides base - emitter
bias voltage.
• Practically immune to changes in βdc due
to transistor replacement or temperature
variation.
• Q point to be in active region for use in
amplifier circuits.
28
Voltage Divider Bias
• R1, R2 - potential divider
for base potential and
base current (bias).
• RC - collector resistance
limits collector current.
• RE – provides negative
feedback and controls
gain.
• Very high gain may lead
to transistor saturation.
29
Voltage Divider Bias
VBE
30
Voltage Divider Bias
DC Load Line
Design:
Drop across Rc = 40% of Vcc.
Drop across RE = 10% of Vcc.
VCE = 50% of Vcc .
31
RC Coupled Amplifier
Cin, Cout - coupling
capacitors block dc
from previous/to
next stage and
preserves bias
conditions.
CE – emitter bypass
capacitor bypasses
ac feedback when
ac input signal is
applied.
RL- load
resistance.
Voltage/Potential
Divider Bias
32
Why Coupling Capacitor?
DC Voltage from
Vcc may affect bias
conditions of the
next stage if no
coupling capacitor.
Transistor may go to saturation.
Emitter
Bypass
Capacitor
DC coupled to
the next stage.
33
Why Coupling Capacitor?

1
2
c
X
fC


If Xc – Capacitive Reactance,
f- Input Frequency,
C – Capacitance.
At dc, f = 0. Xc = ,
dc not allowed to
pass through.

1
2
c
X
fC


34
Impact of Coupling Capacitors
Low frequency signal
attenuated, output
amplitude reduces at
low frequencies for a
fixed gain .
High Xc at low f
35
Impact of Emitter Bypass Capacitor
Low Xc at high f
Emitter Bypass
Capacitor CE bypasses
ac drop across RE,
output amplitude
reduces at high
frequencies for a fixed
gain.
36
Impact of Transistor Parasitics
Low Xc at high f Transistor Parasitic
Capacitances shunt
across transistor
leads and reduces
amplifier effective
gain at high
frequencies.
Transistor Stray
Capacitances act as
leaky capacitors.
Stray/Parasitic Capacitances
are symbiotic.
37
Bandwidth of an Amplifier
• Range of frequencies amplified by an
amplifier.
• 3 dB bandwidth the difference between
higher and lower cut off frequencies.
• Frequency response as an inverted
bathtub curve.
• At low frequencies, effective gain reduces
due to coupling capacitor action.
• At high frequencies, effective gain reduces
due to transistor parasitics and emitter
bypass capacitor action.
38
Frequency Response Curve
Midband Gain Constant
Gain reduces below f1 and beyond f2.
(3dB Gain)
39
RC Phase Shift Oscillator with
Voltage Divider Bias
40
Thank You

More Related Content

What's hot

Presentation on bipolar junction transistor
Presentation on bipolar junction transistorPresentation on bipolar junction transistor
Presentation on bipolar junction transistorKawsar Ahmed
 
Lecture 2: Power Diodes
Lecture 2: Power DiodesLecture 2: Power Diodes
Lecture 2: Power Diodesaadesharya
 
Comparison of A, B & C Power Amplifiers
Comparison of A, B & C Power AmplifiersComparison of A, B & C Power Amplifiers
Comparison of A, B & C Power AmplifiersJayanshu Gundaniya
 
Half wave control rectifier with RL load
Half wave control rectifier with RL loadHalf wave control rectifier with RL load
Half wave control rectifier with RL loadSmit Shah
 
Power electronics Phase Controlled Rectifiers - SCR
Power electronics   Phase Controlled Rectifiers - SCRPower electronics   Phase Controlled Rectifiers - SCR
Power electronics Phase Controlled Rectifiers - SCRBurdwan University
 
Rectifiers and Filter Circuits
Rectifiers and Filter CircuitsRectifiers and Filter Circuits
Rectifiers and Filter CircuitsRakesh Sheoran
 
Schering bridge and its derivation
Schering bridge and its derivationSchering bridge and its derivation
Schering bridge and its derivationkaroline Enoch
 
Diode v i characteristic
Diode v i characteristicDiode v i characteristic
Diode v i characteristicUnsa Shakir
 
Silicon controlled rectifier
Silicon controlled rectifierSilicon controlled rectifier
Silicon controlled rectifierpavan chauda
 
Common Emitter Configuration | Electronical Engineering
Common Emitter Configuration | Electronical EngineeringCommon Emitter Configuration | Electronical Engineering
Common Emitter Configuration | Electronical EngineeringTransweb Global Inc
 
Single phase Transformer
Single phase Transformer  Single phase Transformer
Single phase Transformer johny renoald
 

What's hot (20)

Thyristor
ThyristorThyristor
Thyristor
 
Presentation on bipolar junction transistor
Presentation on bipolar junction transistorPresentation on bipolar junction transistor
Presentation on bipolar junction transistor
 
MOSFETs
MOSFETsMOSFETs
MOSFETs
 
Lecture 2: Power Diodes
Lecture 2: Power DiodesLecture 2: Power Diodes
Lecture 2: Power Diodes
 
Comparison of A, B & C Power Amplifiers
Comparison of A, B & C Power AmplifiersComparison of A, B & C Power Amplifiers
Comparison of A, B & C Power Amplifiers
 
Hybrid Parameter in BJT
Hybrid Parameter in BJTHybrid Parameter in BJT
Hybrid Parameter in BJT
 
igbt and its characteristics
igbt and its characteristicsigbt and its characteristics
igbt and its characteristics
 
Half wave control rectifier with RL load
Half wave control rectifier with RL loadHalf wave control rectifier with RL load
Half wave control rectifier with RL load
 
Power electronics Phase Controlled Rectifiers - SCR
Power electronics   Phase Controlled Rectifiers - SCRPower electronics   Phase Controlled Rectifiers - SCR
Power electronics Phase Controlled Rectifiers - SCR
 
Rectifiers and Filter Circuits
Rectifiers and Filter CircuitsRectifiers and Filter Circuits
Rectifiers and Filter Circuits
 
Schering bridge and its derivation
Schering bridge and its derivationSchering bridge and its derivation
Schering bridge and its derivation
 
SCR.pptx
SCR.pptxSCR.pptx
SCR.pptx
 
Mosfet
MosfetMosfet
Mosfet
 
Transistor configurations
Transistor configurationsTransistor configurations
Transistor configurations
 
Diode v i characteristic
Diode v i characteristicDiode v i characteristic
Diode v i characteristic
 
Thyristor
Thyristor Thyristor
Thyristor
 
Silicon controlled rectifier
Silicon controlled rectifierSilicon controlled rectifier
Silicon controlled rectifier
 
Common Emitter Configuration | Electronical Engineering
Common Emitter Configuration | Electronical EngineeringCommon Emitter Configuration | Electronical Engineering
Common Emitter Configuration | Electronical Engineering
 
Single phase Transformer
Single phase Transformer  Single phase Transformer
Single phase Transformer
 
Semiconductor diodes
Semiconductor diodesSemiconductor diodes
Semiconductor diodes
 

Similar to EST 130, Transistor Biasing and Amplification.

Transistors handout
Transistors handoutTransistors handout
Transistors handoutEng Mahamed
 
BJT Biasing for B.Tech Ist Year Engineering
BJT Biasing for B.Tech Ist Year EngineeringBJT Biasing for B.Tech Ist Year Engineering
BJT Biasing for B.Tech Ist Year EngineeringRaghav Bansal
 
Generation of electrical oscillations with lc circuit
Generation of electrical oscillations with lc circuitGeneration of electrical oscillations with lc circuit
Generation of electrical oscillations with lc circuithepzijustin
 
ELectronic Circuits I
ELectronic Circuits I ELectronic Circuits I
ELectronic Circuits I SreeDeviE_1255
 
Bjt amplifiers
Bjt amplifiersBjt amplifiers
Bjt amplifiersGastarot
 
dc biasing of bjt
dc biasing of bjtdc biasing of bjt
dc biasing of bjtabhinavmj
 
Electronics 1 : Chapter # 05 : DC Biasing BJT
Electronics 1 : Chapter # 05 : DC Biasing BJTElectronics 1 : Chapter # 05 : DC Biasing BJT
Electronics 1 : Chapter # 05 : DC Biasing BJTSk_Group
 
Class a power amplifiers
Class a power amplifiersClass a power amplifiers
Class a power amplifiersAdarsh Raj
 
Chapter-6 DC biasing-1.ppt
Chapter-6 DC biasing-1.pptChapter-6 DC biasing-1.ppt
Chapter-6 DC biasing-1.pptJeelBhanderi4
 
Electronics 1 : Chapter # 04 : Diode Applications and Types
Electronics 1 : Chapter # 04 : Diode Applications and TypesElectronics 1 : Chapter # 04 : Diode Applications and Types
Electronics 1 : Chapter # 04 : Diode Applications and TypesSk_Group
 
ch4-Power_Amplifier.pptx
ch4-Power_Amplifier.pptxch4-Power_Amplifier.pptx
ch4-Power_Amplifier.pptxNischalBhusal1
 

Similar to EST 130, Transistor Biasing and Amplification. (20)

Transistors handout
Transistors handoutTransistors handout
Transistors handout
 
Transistor applications (2)
Transistor applications (2)Transistor applications (2)
Transistor applications (2)
 
Transistor applications
Transistor applicationsTransistor applications
Transistor applications
 
BJT Biasing for B.Tech Ist Year Engineering
BJT Biasing for B.Tech Ist Year EngineeringBJT Biasing for B.Tech Ist Year Engineering
BJT Biasing for B.Tech Ist Year Engineering
 
Generation of electrical oscillations with lc circuit
Generation of electrical oscillations with lc circuitGeneration of electrical oscillations with lc circuit
Generation of electrical oscillations with lc circuit
 
ELectronic Circuits I
ELectronic Circuits I ELectronic Circuits I
ELectronic Circuits I
 
Transistor as a switch (1)
Transistor as a switch (1)Transistor as a switch (1)
Transistor as a switch (1)
 
Transistor as a switch
Transistor as a switchTransistor as a switch
Transistor as a switch
 
Transistor as a switch (4)
Transistor as a switch (4)Transistor as a switch (4)
Transistor as a switch (4)
 
Transistor as a switch (2)
Transistor as a switch (2)Transistor as a switch (2)
Transistor as a switch (2)
 
Transistor as a switch (3)
Transistor as a switch (3)Transistor as a switch (3)
Transistor as a switch (3)
 
Bjt amplifiers
Bjt amplifiersBjt amplifiers
Bjt amplifiers
 
dc biasing of bjt
dc biasing of bjtdc biasing of bjt
dc biasing of bjt
 
Electronics 1 : Chapter # 05 : DC Biasing BJT
Electronics 1 : Chapter # 05 : DC Biasing BJTElectronics 1 : Chapter # 05 : DC Biasing BJT
Electronics 1 : Chapter # 05 : DC Biasing BJT
 
Class a power amplifiers
Class a power amplifiersClass a power amplifiers
Class a power amplifiers
 
Chapter-6 DC biasing-1.ppt
Chapter-6 DC biasing-1.pptChapter-6 DC biasing-1.ppt
Chapter-6 DC biasing-1.ppt
 
ELECTRONICS DEVICES AND CIRCUITS
ELECTRONICS DEVICES AND CIRCUITSELECTRONICS DEVICES AND CIRCUITS
ELECTRONICS DEVICES AND CIRCUITS
 
bjt ppt project.ppt
bjt ppt  project.pptbjt ppt  project.ppt
bjt ppt project.ppt
 
Electronics 1 : Chapter # 04 : Diode Applications and Types
Electronics 1 : Chapter # 04 : Diode Applications and TypesElectronics 1 : Chapter # 04 : Diode Applications and Types
Electronics 1 : Chapter # 04 : Diode Applications and Types
 
ch4-Power_Amplifier.pptx
ch4-Power_Amplifier.pptxch4-Power_Amplifier.pptx
ch4-Power_Amplifier.pptx
 

More from CKSunith1

EST 130, Modulation
EST 130, ModulationEST 130, Modulation
EST 130, ModulationCKSunith1
 
EST 200, Design Thinking in Automobile Industry
EST 200, Design Thinking in Automobile IndustryEST 200, Design Thinking in Automobile Industry
EST 200, Design Thinking in Automobile IndustryCKSunith1
 
EST 130, Bipolar Junction Transistors
EST 130, Bipolar Junction TransistorsEST 130, Bipolar Junction Transistors
EST 130, Bipolar Junction TransistorsCKSunith1
 
CSL 202, Shift Registers using Flipflops
CSL 202, Shift Registers using FlipflopsCSL 202, Shift Registers using Flipflops
CSL 202, Shift Registers using FlipflopsCKSunith1
 
EST 130, PN Junction Diodes
EST 130, PN Junction DiodesEST 130, PN Junction Diodes
EST 130, PN Junction DiodesCKSunith1
 
EST 200, Oral and Written Communications
EST 200, Oral and Written CommunicationsEST 200, Oral and Written Communications
EST 200, Oral and Written CommunicationsCKSunith1
 
CSL 202, Counters using Flipflops
CSL 202, Counters using FlipflopsCSL 202, Counters using Flipflops
CSL 202, Counters using FlipflopsCKSunith1
 
EST 200, Designing Triggers for Behavior Change
EST 200, Designing Triggers for Behavior ChangeEST 200, Designing Triggers for Behavior Change
EST 200, Designing Triggers for Behavior ChangeCKSunith1
 
EST 200, Communicating Designs Graphically
EST 200, Communicating Designs GraphicallyEST 200, Communicating Designs Graphically
EST 200, Communicating Designs GraphicallyCKSunith1
 
EST 130, Semiconductors
EST 130, SemiconductorsEST 130, Semiconductors
EST 130, SemiconductorsCKSunith1
 
EST 200, Design Thinking in Teams
EST 200, Design Thinking in TeamsEST 200, Design Thinking in Teams
EST 200, Design Thinking in TeamsCKSunith1
 
EST 200, Design Thinking in a Work Place.
EST 200, Design Thinking in a Work Place.EST 200, Design Thinking in a Work Place.
EST 200, Design Thinking in a Work Place.CKSunith1
 
CSL 202, Flipflops using Logic Gates
CSL 202, Flipflops using Logic GatesCSL 202, Flipflops using Logic Gates
CSL 202, Flipflops using Logic GatesCKSunith1
 
EST 200, Convergent and Divergent Thinking
EST 200, Convergent and Divergent ThinkingEST 200, Convergent and Divergent Thinking
EST 200, Convergent and Divergent ThinkingCKSunith1
 
EST 200, Design Thinking in a Work Place
EST 200, Design Thinking in a Work PlaceEST 200, Design Thinking in a Work Place
EST 200, Design Thinking in a Work PlaceCKSunith1
 
EST 200, Design Thinking
EST 200, Design ThinkingEST 200, Design Thinking
EST 200, Design ThinkingCKSunith1
 
EST 130, Identifying Active Components
EST 130, Identifying Active ComponentsEST 130, Identifying Active Components
EST 130, Identifying Active ComponentsCKSunith1
 
CSL 202, Multiplexer and Demultiplexer
CSL 202, Multiplexer and DemultiplexerCSL 202, Multiplexer and Demultiplexer
CSL 202, Multiplexer and DemultiplexerCKSunith1
 
Est 130 passive components inductors
Est 130 passive components inductorsEst 130 passive components inductors
Est 130 passive components inductorsCKSunith1
 
EST 200, Evaluating Design Alternatives
EST 200, Evaluating Design AlternativesEST 200, Evaluating Design Alternatives
EST 200, Evaluating Design AlternativesCKSunith1
 

More from CKSunith1 (20)

EST 130, Modulation
EST 130, ModulationEST 130, Modulation
EST 130, Modulation
 
EST 200, Design Thinking in Automobile Industry
EST 200, Design Thinking in Automobile IndustryEST 200, Design Thinking in Automobile Industry
EST 200, Design Thinking in Automobile Industry
 
EST 130, Bipolar Junction Transistors
EST 130, Bipolar Junction TransistorsEST 130, Bipolar Junction Transistors
EST 130, Bipolar Junction Transistors
 
CSL 202, Shift Registers using Flipflops
CSL 202, Shift Registers using FlipflopsCSL 202, Shift Registers using Flipflops
CSL 202, Shift Registers using Flipflops
 
EST 130, PN Junction Diodes
EST 130, PN Junction DiodesEST 130, PN Junction Diodes
EST 130, PN Junction Diodes
 
EST 200, Oral and Written Communications
EST 200, Oral and Written CommunicationsEST 200, Oral and Written Communications
EST 200, Oral and Written Communications
 
CSL 202, Counters using Flipflops
CSL 202, Counters using FlipflopsCSL 202, Counters using Flipflops
CSL 202, Counters using Flipflops
 
EST 200, Designing Triggers for Behavior Change
EST 200, Designing Triggers for Behavior ChangeEST 200, Designing Triggers for Behavior Change
EST 200, Designing Triggers for Behavior Change
 
EST 200, Communicating Designs Graphically
EST 200, Communicating Designs GraphicallyEST 200, Communicating Designs Graphically
EST 200, Communicating Designs Graphically
 
EST 130, Semiconductors
EST 130, SemiconductorsEST 130, Semiconductors
EST 130, Semiconductors
 
EST 200, Design Thinking in Teams
EST 200, Design Thinking in TeamsEST 200, Design Thinking in Teams
EST 200, Design Thinking in Teams
 
EST 200, Design Thinking in a Work Place.
EST 200, Design Thinking in a Work Place.EST 200, Design Thinking in a Work Place.
EST 200, Design Thinking in a Work Place.
 
CSL 202, Flipflops using Logic Gates
CSL 202, Flipflops using Logic GatesCSL 202, Flipflops using Logic Gates
CSL 202, Flipflops using Logic Gates
 
EST 200, Convergent and Divergent Thinking
EST 200, Convergent and Divergent ThinkingEST 200, Convergent and Divergent Thinking
EST 200, Convergent and Divergent Thinking
 
EST 200, Design Thinking in a Work Place
EST 200, Design Thinking in a Work PlaceEST 200, Design Thinking in a Work Place
EST 200, Design Thinking in a Work Place
 
EST 200, Design Thinking
EST 200, Design ThinkingEST 200, Design Thinking
EST 200, Design Thinking
 
EST 130, Identifying Active Components
EST 130, Identifying Active ComponentsEST 130, Identifying Active Components
EST 130, Identifying Active Components
 
CSL 202, Multiplexer and Demultiplexer
CSL 202, Multiplexer and DemultiplexerCSL 202, Multiplexer and Demultiplexer
CSL 202, Multiplexer and Demultiplexer
 
Est 130 passive components inductors
Est 130 passive components inductorsEst 130 passive components inductors
Est 130 passive components inductors
 
EST 200, Evaluating Design Alternatives
EST 200, Evaluating Design AlternativesEST 200, Evaluating Design Alternatives
EST 200, Evaluating Design Alternatives
 

Recently uploaded

A Domino Admins Adventures (Engage 2024)
A Domino Admins Adventures (Engage 2024)A Domino Admins Adventures (Engage 2024)
A Domino Admins Adventures (Engage 2024)Gabriella Davis
 
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...apidays
 
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptxEIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptxEarley Information Science
 
Injustice - Developers Among Us (SciFiDevCon 2024)
Injustice - Developers Among Us (SciFiDevCon 2024)Injustice - Developers Among Us (SciFiDevCon 2024)
Injustice - Developers Among Us (SciFiDevCon 2024)Allon Mureinik
 
How to convert PDF to text with Nanonets
How to convert PDF to text with NanonetsHow to convert PDF to text with Nanonets
How to convert PDF to text with Nanonetsnaman860154
 
How to Troubleshoot Apps for the Modern Connected Worker
How to Troubleshoot Apps for the Modern Connected WorkerHow to Troubleshoot Apps for the Modern Connected Worker
How to Troubleshoot Apps for the Modern Connected WorkerThousandEyes
 
Presentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreterPresentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreternaman860154
 
Automating Google Workspace (GWS) & more with Apps Script
Automating Google Workspace (GWS) & more with Apps ScriptAutomating Google Workspace (GWS) & more with Apps Script
Automating Google Workspace (GWS) & more with Apps Scriptwesley chun
 
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...Drew Madelung
 
A Call to Action for Generative AI in 2024
A Call to Action for Generative AI in 2024A Call to Action for Generative AI in 2024
A Call to Action for Generative AI in 2024Results
 
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptxHampshireHUG
 
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live StreamsTop 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live StreamsRoshan Dwivedi
 
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law DevelopmentsTrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law DevelopmentsTrustArc
 
[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdf[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdfhans926745
 
2024: Domino Containers - The Next Step. News from the Domino Container commu...
2024: Domino Containers - The Next Step. News from the Domino Container commu...2024: Domino Containers - The Next Step. News from the Domino Container commu...
2024: Domino Containers - The Next Step. News from the Domino Container commu...Martijn de Jong
 
GenCyber Cyber Security Day Presentation
GenCyber Cyber Security Day PresentationGenCyber Cyber Security Day Presentation
GenCyber Cyber Security Day PresentationMichael W. Hawkins
 
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...Neo4j
 
08448380779 Call Girls In Friends Colony Women Seeking Men
08448380779 Call Girls In Friends Colony Women Seeking Men08448380779 Call Girls In Friends Colony Women Seeking Men
08448380779 Call Girls In Friends Colony Women Seeking MenDelhi Call girls
 
The Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptxThe Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptxMalak Abu Hammad
 
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...Miguel Araújo
 

Recently uploaded (20)

A Domino Admins Adventures (Engage 2024)
A Domino Admins Adventures (Engage 2024)A Domino Admins Adventures (Engage 2024)
A Domino Admins Adventures (Engage 2024)
 
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...
Apidays Singapore 2024 - Building Digital Trust in a Digital Economy by Veron...
 
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptxEIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
 
Injustice - Developers Among Us (SciFiDevCon 2024)
Injustice - Developers Among Us (SciFiDevCon 2024)Injustice - Developers Among Us (SciFiDevCon 2024)
Injustice - Developers Among Us (SciFiDevCon 2024)
 
How to convert PDF to text with Nanonets
How to convert PDF to text with NanonetsHow to convert PDF to text with Nanonets
How to convert PDF to text with Nanonets
 
How to Troubleshoot Apps for the Modern Connected Worker
How to Troubleshoot Apps for the Modern Connected WorkerHow to Troubleshoot Apps for the Modern Connected Worker
How to Troubleshoot Apps for the Modern Connected Worker
 
Presentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreterPresentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreter
 
Automating Google Workspace (GWS) & more with Apps Script
Automating Google Workspace (GWS) & more with Apps ScriptAutomating Google Workspace (GWS) & more with Apps Script
Automating Google Workspace (GWS) & more with Apps Script
 
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
 
A Call to Action for Generative AI in 2024
A Call to Action for Generative AI in 2024A Call to Action for Generative AI in 2024
A Call to Action for Generative AI in 2024
 
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
 
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live StreamsTop 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
 
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law DevelopmentsTrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
 
[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdf[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdf
 
2024: Domino Containers - The Next Step. News from the Domino Container commu...
2024: Domino Containers - The Next Step. News from the Domino Container commu...2024: Domino Containers - The Next Step. News from the Domino Container commu...
2024: Domino Containers - The Next Step. News from the Domino Container commu...
 
GenCyber Cyber Security Day Presentation
GenCyber Cyber Security Day PresentationGenCyber Cyber Security Day Presentation
GenCyber Cyber Security Day Presentation
 
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
 
08448380779 Call Girls In Friends Colony Women Seeking Men
08448380779 Call Girls In Friends Colony Women Seeking Men08448380779 Call Girls In Friends Colony Women Seeking Men
08448380779 Call Girls In Friends Colony Women Seeking Men
 
The Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptxThe Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptx
 
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
 

EST 130, Transistor Biasing and Amplification.

  • 1. 1 EST 130, Transistor Biasing and Amplification MEC
  • 2. 2 Contents • Need for Biasing. • Load Line and Q-Point. • Transistor Operating Regions. • Common Transistor Bias Circuits. • Voltage Divider Bias. • Common Emitter RC Coupled Amplifier. • Use of Coupling Capacitors. • Frequency Response.
  • 3. 3 Transistor Biasing • Bias defined as a control voltage or current. • External dc supply voltage applied to produce the desired collector current. • Transistors biased correctly to produce the desired circuit voltages and currents. • Different biasing techniques - base bias, voltage divider bias, emitter bias etc.
  • 4. 4 Transistor Operating Regions Operating Region Emitter – Base Junction Collector – Base Junction Applications Active Region Forward Biased Reverse Biased Amplifiers, Oscillators Saturation Region Forward Biased Forward Biased Switches (on/off) Cut off Region Reverse Biased Reverse Biased Inverse Active Region Reverse Biased Forward Biased Not normally used
  • 5. 5 Transistor Equations • When transistor is in saturation, Ic = Ic(sat) and Vce ≈ 0V, Ic(sat) = Vcc/Rc. • Ic(sat) is the maximum current that can flow through Rc. • When transistor is at cut off, Ic ≈ 0, Vce = Vce(off) = Vcc.
  • 6. 6 DC Load Line • A graph that shows possible combinations of IC and VCE for a given amplifier. • Endpoints of dc load line labeled IC(sat) & VCE(off) • IC(sat) - collector current IC when transistor saturated. • VCE(off) - collector- emitter voltage with IC = 0 for cutoff. Cut Off Saturation Active Region Collector to Emitter Voltage Collector Current
  • 7. 7 Shift in Load Line with Collector Resistance When Rc↑ IC↓, load line shifts. Vcc unchanged
  • 8. 8 Shift in Load Line with Supply Voltage Rc unchanged
  • 9. 9 Biasing Point • Represents the collector to emitter voltage and collector current of the transistor at any instant. • Biasing point to lie along the dc load line. • Also called Quiescent Point (Q-point) or the operating point. • Q stands for quiescent currents and voltages with no ac input signal applied.
  • 10. 10 Biasing Point • Without ac signal applied to a transistor, specific values of IC and VCE exist. • IC and VCE values exist at a specific point on the dc load line. • Q Point to lie in active region for transistor amplifiers. • Q Point swings between saturation and cut off for transistor switches.
  • 11. 11 Q-Point • Amplifiers biased with Q point at or near the center of the dc load line (active region). • ICQ = 1⁄2 IC(sat) and VCEQ = VCC /2. Biasing for stability of Q-Point.
  • 12. 12 Q-Point • AC input signal adds to the bias voltage at the base. • Q Point swings up and down along the dc load line when ac input signal applied to the base. • Swing to lie within the active region for proper amplification. • Q-Point preferably to be centered around midpoint of the dc load line for amplifiers.
  • 14. 14 Transistor in Saturation  When a transistor is saturated: • further increases in IB produce no further increases in IC . • the collector circuit no longer acts like a current source since VCE ≈ 0 and the collector-base junction of the transistor is not properly reverse-biased. • treat the collector-emitter region like a short circuit.
  • 15. 15 Transistor at Cut Off When the transistor is cut off: • visualize the collector-emitter region as an open circuit because IC ≈ 0. • with zero collector current, ICRC voltage drop is zero. • resultant collector-emitter voltage VCE ≈ VCC.
  • 16. 16 Transistor in Active Region  When a transistor is operating in the active region: • IC = βdc x IB. • collector circuit acts as a current source with high internal impedance.
  • 17. 17 Q-Point Swing in Active Region Q-Point to be at the centre of the load line for maximum possible output swing.
  • 18. 18 Q-Point Swing Temperature variations may affect Q-Point Stability. Bias for thermal stability of Q-Point.
  • 19. 19 Q-Point for Faithful Amplification Output Voltage Collector Current Input
  • 20. 20 Q-Point Swing Shaded portion removed, distorts output waveform when Q-Point is at cut off.
  • 21. 21 Q-Point Swing Shaded portion removed, distorts output waveform when Q-Point is in saturation.
  • 22. 22 Q-Point Swing Q-Point Swings to Saturation Q-Point Swings to Cutoff Clipped Off Clipped Off Output Output
  • 23. 23 Base Bias • Simplest way to bias a transistor. • Base supply voltage VBB to forward-bias the base-emitter junction. • Supply voltage Vcc provides the reverse- bias voltage required for the collector-base junction. VB E
  • 24. 24 Base Bias with Single Supply A single supply Vcc provides both base and collector bias VBE
  • 25. 25 Base Bias • Unstable Q point since collector current IC and collector-emitter voltage, VCE affected by changes in transistor beta (βdc) value. • Q point might shift to a point located near or at either cutoff or saturation when transistor replaced. • Beta varies with temperature. • Change in the temperature can cause Q point to shift.
  • 26. 26 Emitter Bias • Solid Q point, fluctuates very little with temperature variation & transistor replacement. • Emitter supply voltage VEE forward- biases the emitter- base junction.
  • 27. 27 Voltage Divider Bias • More stable and popular than other biasing arrangements. • A potential divider provides base - emitter bias voltage. • Practically immune to changes in βdc due to transistor replacement or temperature variation. • Q point to be in active region for use in amplifier circuits.
  • 28. 28 Voltage Divider Bias • R1, R2 - potential divider for base potential and base current (bias). • RC - collector resistance limits collector current. • RE – provides negative feedback and controls gain. • Very high gain may lead to transistor saturation.
  • 30. 30 Voltage Divider Bias DC Load Line Design: Drop across Rc = 40% of Vcc. Drop across RE = 10% of Vcc. VCE = 50% of Vcc .
  • 31. 31 RC Coupled Amplifier Cin, Cout - coupling capacitors block dc from previous/to next stage and preserves bias conditions. CE – emitter bypass capacitor bypasses ac feedback when ac input signal is applied. RL- load resistance. Voltage/Potential Divider Bias
  • 32. 32 Why Coupling Capacitor? DC Voltage from Vcc may affect bias conditions of the next stage if no coupling capacitor. Transistor may go to saturation. Emitter Bypass Capacitor DC coupled to the next stage.
  • 33. 33 Why Coupling Capacitor?  1 2 c X fC   If Xc – Capacitive Reactance, f- Input Frequency, C – Capacitance. At dc, f = 0. Xc = , dc not allowed to pass through.  1 2 c X fC  
  • 34. 34 Impact of Coupling Capacitors Low frequency signal attenuated, output amplitude reduces at low frequencies for a fixed gain . High Xc at low f
  • 35. 35 Impact of Emitter Bypass Capacitor Low Xc at high f Emitter Bypass Capacitor CE bypasses ac drop across RE, output amplitude reduces at high frequencies for a fixed gain.
  • 36. 36 Impact of Transistor Parasitics Low Xc at high f Transistor Parasitic Capacitances shunt across transistor leads and reduces amplifier effective gain at high frequencies. Transistor Stray Capacitances act as leaky capacitors. Stray/Parasitic Capacitances are symbiotic.
  • 37. 37 Bandwidth of an Amplifier • Range of frequencies amplified by an amplifier. • 3 dB bandwidth the difference between higher and lower cut off frequencies. • Frequency response as an inverted bathtub curve. • At low frequencies, effective gain reduces due to coupling capacitor action. • At high frequencies, effective gain reduces due to transistor parasitics and emitter bypass capacitor action.
  • 38. 38 Frequency Response Curve Midband Gain Constant Gain reduces below f1 and beyond f2. (3dB Gain)
  • 39. 39 RC Phase Shift Oscillator with Voltage Divider Bias