1. a) Explain the following terms
.i. Intrinsic semiconductor
i.
Extrinsic semiconductor
ii.
Valence Band
iii.
Conduction Band
iv. Energy Gap
2. a) Using diagram elaborate the breakdown of Bipolar Junction Transistor
Find
c) In a negative feedback amplifier A= 100, B=0.04 and V= 50 mV.
1. gain with feedback
2. output voltage
3. Feedback factor
3. a) Using diagram of common Emitter circuit configuration
b) Drive the relationship between a and ẞ in common Emitter circuit configuration
c) The following current reading are obtained in a transistor connection in Common Base
configuration = 10mA and I = 50 μA compute the value of a and Ic
4. a) Using diagram differentiate between P-type and N-type extrinsic semiconductors
b) With aid of diagram explain majority and minority charge carriers
c) Explain in details the principal of forward and reverse characteristic
5a) With the help of a simple energy band diagram, briefly explain conductors, insulators and
semiconductors
(a) If nis the number of excited electrons and N = N is a constant, show that the fraction of
Am
electrons in the conduction band of a semiconductor is given by -
band gap energy in Joules.
= e
5/2KT.
Where E is the
(b) Assuming the number of electrons near the top of the valence band available for thermal
excitation is 5×1025/m³ and the intrinsic carrier density is 2.5×1019/m³. Find the energy gap of
germanium at room temperature.
6.a) Draw the equivalent circuit of common collector and common base circuit configuration
and explain the Transistor biasing rule.
b) Define the term oscillator
c) Write down the comparison between amplifier and oscillator with help of diagram
7a) Briefly explain the physical description of a p-n junction diode.
b)Draw and explain the circuit symbol of a p-n junction diode
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