Objective : To determine operational range of a BJT
Equipments and Components : 1. Resistor : 220kΩ, 1kΩ 2. BJT : BC 108 3. Capacitor : 2 x 10µF 4. Function generator 5. Multimeter 6. Oscilloscope 7. Connecting wires
Procedures :
1. The circuit as shown above is assemble. All terminal connections are ensured
correct. The transistor diagram and its symbol is drawn. 2. The 20mVp-p IkHz sinusoidal wave is applied at the AC input terminal 3. By using the multimeter, the values of IB, IC, VCE, VB, VC and VBC are measured
4. The results obtained are verified by calculation. 5. The AC output signal observed by oscilloscope is drawn.
Result : a) Transistor diagram and its symbol
Simple circuit using a transistor
Schematic symbols for PNP- and NPN-type BJT.
b) Experimental Data
Voltages / Currents IB IC VCE VB VC VBC
Values 0.0367 mA 0.0001 mA 4.14 V 8.35 V 4.95 V 3.39 V
c) Theoretical data 1. Example calculation: VCC
=
IBRB + VBE
IB
=
VCC - VBE RB
=
12 – 0.7 270
=
41.85 µA
=
β IB
=
110 (41.85 µA)
=
4.6035 mA
VCC
=
ICRC + VCE
VCE
=
12 – (4.6035 mA) (2.2 k)
=
1.87 V
=
VCE
IC
VC
=
1.87 V
VB
=
VBE
=
VBC
=
0.7 – 1.87
0.7 V
=
- 1.17 V
Discussion :
Suggestions for further work in the future: 1. Prepare the electrical and electronic components which in good condition. 2. Do not use red maker while writing on the whiteboard because it is unclear. 3. Use LCD projector to show how to do the experiment. 4. Use microphone to give the explanation.
Conclusions: The operational range of a BJT was determined
References: 1. J. David Irwin, Basic Engineering Circuit Analysis, (7th Edition), John Wiley and
Sons Inc,2002
2. David E. Johnson, John L. Hilburn, Johnny R. Johnson, Peter D. Scott, Basic
Electric Circuit Analysis, (5th Edition), Prentice Hall, 1995 3. Robert J. Herrick, DC/AC Circuits and Electronics: Principles & Applications, Theorem Delwan Learning, New York, 2003 4. Thomas L. Floyd, Principles Of Electric Circuits: Electron Flow Version, (3rd
Edition), Macmillan Publishing Company, New York, 1993 5. Thomas L. Floyd, Principles Of Electric Circuits: Conventional Current Versions,
(8th Edition), Pearson Prentice Hall, New Jersey, 2007
