1 Electronic Circuits AMPLIFIERS. 2 Demostrate Transistor Amplification Determine Transistor...
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Transcript of 1 Electronic Circuits AMPLIFIERS. 2 Demostrate Transistor Amplification Determine Transistor...
1
Electronic CircuitsElectronic Circuits
AMPLIFIERSAMPLIFIERS
2
• Demostrate Transistor Amplification
• Determine Transistor Biasing.
• Explain Transistor Regions - Emitter, Base, Collector.
• Explore Transistors as Switches
Objectives
Electronic CircuitsElectronic Circuits
3
Amplifier Out
InGain=
In
Out
Electronic CircuitsElectronic Circuits
4
N
P
NThe collector is lightly doped. C
The base is thin and is lightly doped.
B
The emitter is heavily doped. E
NPN Transistor Structure
Electronic CircuitsElectronic Circuits
5
The C-B junction is reverse biased.
N
P
N
NPN Transistor Bias
C
B
E
No current flows.
Electronic CircuitsElectronic Circuits
6
The B-E junction is forward biased.
N
P
N
NPN Transistor Bias
C
B
E
Current flows.
Electronic CircuitsElectronic Circuits
7
When both junctionsare biased....
N
P
N
NPN Transistor Bias
C
B
E
Current flowseverywhere.
Most of the emitter carriersdiffuse through the thin base
region since they are attractedby the collector.
Note that IB is smallerthan IE or IC.
IC
IB
IE
Electronic CircuitsElectronic Circuits
8
N
P
N C
B
E
Although IB is smallerit controls IE and IC.
IC
IB
IE
Note: when the switch opens, all
currents go to zero.
Gain is something smallcontrolling something large
(IB is small).
Electronic CircuitsElectronic Circuits
9
Amplifier Out
InGain=
In
Out
Electronic CircuitsElectronic Circuits
10
The C-B junction is reverse biased.
N
P
N
NPN Transistor Bias
C
B
E
No current flows.
Electronic CircuitsElectronic Circuits
11
The B-E junction is forward biased.
N
P
N
NPN Transistor Bias
C
B
E
Current flows.
Electronic CircuitsElectronic Circuits
12
When both junctionsare biased....
N
P
N
NPN Transistor Bias
C
B
E
Current flowseverywhere.
Most of the emitter carriersdiffuse through the thin base
region since they are attractedby the collector.
Note that IB is smallerthan IE or IC.
IC
IB
IE
Electronic CircuitsElectronic Circuits
13
N
P
N C
B
E
Although IB is smallerit controls IE and IC.
IC
IB
IE
Note: when the switch opens, all
currents go to zero.
Gain is something smallcontrolling something large
(IB is small).
Electronic CircuitsElectronic Circuits
14
Transistor Structure and Bias QuizThe heaviest doping is found in the ___________ region.
emitter
The thinnest of all three regions is called the ____________.
base
The collector-base junction is ___________ biased. reverse
The base-emitter junction is ____________ biased. forward
The majority of the emitter carriers flow to the ___________. collector
Electronic CircuitsElectronic Circuits