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Name:
Matric No:
Section:
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
MID TERM EXAMINATION
SEMESTER I, 2016/2017 SESSION
KULLIYYAH OF ENGINEERING
Program
Time
Duration
Section(s)
Course Title
: ENGINEERING
: 08.00 pm – 10.00 pm
: 2 hours
: 1-7
: Electronics
Level of Study
Date
Course Code
: UG1
: 03/11/2016
: EECE1312/ECE1312
This Question Paper Consists of Ten (10) Printed Pages Including Cover Page With four (4)
Questions.
INSTRUCTION(S) TO CANDIDATES
DO NOT OPEN UNTIL YOU ARE ASKED TO DO SO



Total marks of this examination is 60.
This examination is worth 25% of the total assessment
Answer all 3 (THREE) questions.
Any form of cheating or attempt to cheat is a serious offence which may
lead to dismissal.
Q No.
Total
Obtain
Question 1 (20)
a)
b)
c)
8
6
6
Question 2 (20)
a)
b)
c)
6
6
8
Question 3 (20)
a)
b)
c)
8
8
4
Total (60)
Total
1
Question 1 [20 marks]
a) The short circuit current of a current amplifier is 100 mA when its input is connected to a
signal source. The voltage of the signal source is 10 V and its resistance is 3 kΩ. The input
and output resistances of the amplifier are 1 kΩ and 100 Ω respectively.
(2+3+3 marks)
i.
ii.
iii.
Draw the schematic of the amplifier circuit including the source.
Calculate the short circuit current gain of the amplifier
Determine the output current and voltage of the amplifier when a 25 Ω load
resistor is connected at the output.
b) Calculate the output voltage, VO and voltage gain, AV of the ideal operational amplifier as
shown in Fig.1(b).
(6 marks)
Fig. 1(b)
c)
Design the non-inverting operational amplifier circuit as shown in Fig.1 (c) to produce an
output voltage, VO of 9.5 V.
(6 marks)
Fig. 1(c)
2
Question 2 [20 marks]
a) Calculate the built-in potential barrier of a silicon pn junction diode. Consider the diode is
operating at room temperature (300°K). Assume that p-type semiconductor is doped at
Na = 1.2 × 1016 cm-3 and n-type semiconductors is doped at Nd = 1.8 × 1017 cm-3.
(Where, Eg = 1.1 eV , B = 5.23 × 1015 cm-3 K-3/2, k = 86 x 10-6 eV/K and VT = 26 mV)
(6 marks)
b) A forward bias pn junction diode has the current ID = 3.5 mA. Consider that diode is
operating at room temperature (300°K).
If the reverse saturation current, IS = 1.5×10-11 mA and n = 1, determine the diode voltage VD.
(6 marks)
c) A diode circuit and its load line are as shown in Fig. 2(c).
(2+6 marks)
Fig. 2(c)
i.
ii.
Design the circuit when the diode is operating in forward bias condition.
Determine the diode current ID and diode forward resistance rf in the circuit using a
piecewise linear model. Consider the cut-in voltage of the diode, Vγ = 0.65V.
3
Question 3 [15 marks]
a) A half wave rectifier circuit is shown in Fig. 3(a). Assume that the diode cut in voltage
Vγ = 0.7V. The transformer primary is connected to an AC source voltage, vp (rms) = 220V
(6+2 marks)
Fig. 3(a)
i. Design the circuit so that the peak output voltage, vo (peak) = 9V.
ii. Calculate the peak current in the circuit for load resistance RL = 50 Ω.
b) A full-wave bridge rectifier battery charger circuit is as shown in Fig. 3(b). Assume that the
diode cut in voltage Vγ = 0.7 V and forward resistance rf = 10 Ω. The transformer primary is
connected to the AC power supply voltage, vp = 156 sin (t) V. Determine the peak charging
current of the battery and maximum reverse biased voltage of the diode.
Assume that the transformer coils turn ratio, N1:N2 = 20:1 and the battery voltage VB = 3.6 V
(5+3 marks)
Fig. 3(b)
4
c) A diode circuit is as shown in Fig. 3(c). Assume that the circuit parameters are R1 = 3 kΩ,
R2 = 1 kΩ, Vγ = 0.7 V, V + = +6 V and V - = -5 V
Determine the values of the output voltage, VO and the diode current, ID of the circuit.
(4 marks)
Fig. 3(c)
5