Characteristic
of Tranistor in CE configuration
Object: To draw and study the
characteristic of PNP transistor in
common emitter configuration.
Apparatus used: Transistor,
variable DC source of range 0-3 volt and 0-15volts, voltmeter of range 0-3 and
0-15volt, mili-ammeter, wires/leads.
Theory: There are four characteristic curves of
transistor in common emitter configuration which are defined as follows.
Input characteristic: The variation of input
current (IB) with input voltage (VBE) at constant output
voltage (VE) provides the input characteristics. Input resistance
can be obtained by this characteristic curve.
Output characteristic: The variation of output
current (IC) with output voltage (VCE) at constant input
current (IB) provides the output characteristics. Output admittance
and output resistance can be determined with help of this characteristic curve.
Forward current transfer characteristic: The
variation of output current (IC) with input current (IB)
at constant output voltage (VCB) provides the forward current
transfer characteristics. The slop of curve gives the DC current gain in CE
configuration.
Reverse voltage transfer characteristic: The
variation of input voltage (VBE) with output voltage (VCE)
at constant input current (IB) provides the reverse voltage transfer
characteristics.
B. Table for Output characteristic
|
Sr. No. |
VCE (volts) |
|
IC (mA) |
|
|
|
IB=20 μA |
IB=40 μA |
IB=60 μA |
IB=80 μA |
||
|
1. |
0 |
0 |
0 |
0 |
0 |
|
2. |
0.2 |
2.5 |
5.0 |
8.0 |
11.0 |
|
3. |
0.4 |
3.0 |
6.0 |
9.0 |
12.0 |
|
4. |
0.6 |
3.0 |
6.0 |
9.0 |
12.0 |
|
5 |
0.8 |
3.0 |
6.0 |
9.0 |
12.0 |
|
6. |
1 |
3.0 |
6.0 |
9.0 |
12.0 |
|
7. |
2 |
3.0 |
6.0 |
9.0 |
12.0 |
|
8. |
3 |
3.0 |
6.0 |
9.0 |
12.0 |
|
9. |
4 |
3.0 |
6.0 |
9.0 |
12.0 |
|
10. |
5 |
3.0 |
6.0 |
9.0 |
12.0 |
|
11. |
6 |
3.0 |
6.0 |
9.0 |
12.0 |
|
12.. |
7 |
3.0 |
6.0 |
9.0 |
12.0 |
|
13. |
8 |
3.0 |
6.0 |
9.0 |
12.0 |
|
14. |
9 |
3.0 |
6.0 |
9.0 |
12.0 |
Input characteristic Curve
Output characteristic Curve
Result
Input characteristic resembles a forward-biased diode.
Output characteristic shows cut-off, active, and
saturation regions.
Transistor works as an amplifier in active region.
9. Precautions
Ensure correct polarity (especially for PNP/NPN).
Do not exceed voltage/current ratings.
Take readings carefully to avoid fluctuation errors.
Connections should be tight and correct.
