Common Base Transistor Project AIM: 1.To observe and draw the input and output characteristics of a transistor connected in common base configuration. 2. To find α of the given transistor.
wrwqr
common emitter satu tingkat
Physics Investigatory Project on Common Base Transistor and study their input and output characteristics
Rangkaian Penguat CE Satu Tingkat
common emitter satu tingkat
todo sobre el transistorDescripción completa
transistorFull description
transistorFull description
klystron tube
Discusses the natures of doctorates.Full description
COMMON EMITTER TRANSISTOR CHARACTERISTICS
A PHYSICS PHYSICS INVESTIGATO INVESTIGATORY RY PROJECT PROJECT
1. To plot the input and output static characteris tics .
A i m :
2. To calculate the input dynamic resistance from the input characteris tics and output output dynamic resistance and current gain from the output characteristics of the given transistor .
App pparatus Requ ir ed: S.No
Name of t of the
Equipment / /Component
Sp ecif ications
Quantity
1
Transistor (BC 107)
Icmax=100m A PD=300mw Vceo=45V Vbeo=50V
2
Resistors-39KΩ,1KΩ
Power rating=0.5w Carbon type
1
3
Regulated Power S Power Supply
0-30 V,1 A
1
1
4
Volt meters
0-1V, 0-10V
1
5
Ammeters
0-300µ A, 0-10mA
1
Theory: In
common
emitter
configuration
the
emitter
common to both input and output. For operation
the
Base-Emitter
junction
is
is
normal forward
biased and base- collector junction is reveres biased .The input characteristics are plotted between IB and VBE
keeping
the
voltage
VCE
constant.
This
characteristic is very similar to that of a forward biased
diode.
The
input
dynamic
resistance
is
calculated using t h e f o r m u l a r i
= ∆ VBE / ∆ IB at constant VCE
The output characteristics are plotted between I C and VCE keeping IB constant. These curves are almost horizontal. The output dynamic resistance is given by, r o
=
∆VCE / ∆ IC
at constant IB
At a given operating point, we define DC and AC current gains (beta) as f ollows DC current gain βdc = I C / IB VCE
at constant
AC current gain βac = ∆ IC/ ∆ IB
at constant VCE.
Circuit diagr am:
Fig A: Transistor Common Emitter Configuration
P roc edu re: a) Input Character istics: 1. Connect the circuit as shown in fig A. 2. Keep the voltage VCE as constant at 2V by varying VCC. 3. Vary the input voltage, VBB in steps of 1V up to 10V 4. Measure the voltage, VBE from voltmeter and current, I B through the ammeter for different values of input voltages 5. Repeat the step 3 and 4 for VCE values of 5V and 10V 6. Draw input static characteristics for tabulated values 7. At suitable operating point, calculate input dynamic resistance.
b) Output Characteristics: 1. Fix input base current, IB at constant value say at 10µ A. 2. Vary the output voltage, VCC in steps of 1V from 0V up to10V. 3. Measure the voltage, VCE from voltmeter and current IC through the ammeter for different values. 4. Repeat above steps 2and 3 for various values of IB=20µA and 30µ A. 5. Draw output static characteristics for tabulated values
Tabular f orms: a) Input Characteristics: Appli ed
S.No
Volta ge VBB(V)
VCE = 2V
VCE = 5V
VCE = 10V
VBE(V)
IB(µA)
VBE(V)
IB(µA)
V BE(V)
IB(µ A)
1
0
0
0
0
0
0
0
2
0 .2
0.258
0
0.279
0
0.231
0
3
0 .4
0.461
35
0.460
45
0 .474
40
4
0 .6
0.562
60
0.620
60
0 .592
60
5
0 .8
0.609
90
0.629
90
0 .620
90
6
1 .0
0.625
110
0.670
110
0 .662
110
7
2 .0
0.648
140
0.679
140
0 .682
140
8
3 .0
0.654
160
0.681
160
0 .692
160
9
4 .0
0.669
190
0.684
185
0 .724
190
10
5 .0
0.690
210
0.689
210
0 .726
218
b) Output Characteristics:
S. No
Applied voltage Vcc (V)
IB = 10µ A
VCE(V)
IC(mA)
IB = 20 µ A
VCE (V ) IC(mA)
IB = 30µ A
VCE (V)
IC(mA)
1
0
0
0
0
0
0
0
2
0.2
0.02
0
0.02
0
0.02
0
3
0.4
0.06
0
0.05
0
0.04
0
4
0.6
0.08
1.0
0.08
2.2
0.05
2.6
5
0.7
0.1
3.2
0.09
4.5
0.06
4.6
6
0.8
0.12
5.0
0.1
6.2
0.07
6.5
7
1.0
0.21
6.2
0.15
7.0
0.12
7.5
8
2.0
0.31
6.5
0.18
7.5
0.17
7.8
9
3.0
0.51
6.7
0.29
7.7
0.28
9.9
10
4. 0
0.68
6.8
0.34
8.5
0.33
10.0
11
5. 0
0.88
6.9
0.49
8.9
0.39
10.5
Model gr aphs:
Fig C: Output Characteristics
Fig B: Input Characteristics
Calculations: a) Input Characteristics: Input Resistance,
r i = ∆ VBE / ∆ IB at VCE constant = (0.654-0.647) / (90-30) X 10
-6
= 116Ω.
b) Output Characteristics: Output dynamic resistance,
r o =
∆VCE / ∆ IC at I B constant
= (0.9-0.15) / (9.25-7.2) X10
-3
= 365.85Ω. Current gain,
β = ∆ IC / ∆ IB
at VCE constant -3
= (8.8-6.8)10 /10X10
-6
= 200
Precautions: 1. Connections must be done very caref ully. 2. Readings should be noted without parallax error . 3. The applied voltage, current should not exceed the maximum rating of the given transistor .
Result: Input and output characteristics are observed for the given transistor in common emitter configuration. The input resistance, output resistance and the current gain are calculated.
Inf er ence: It is observed from the input characteristics that as V CE increases, the curves are
shifted towards right side. This is due to the Early eff ect.
