اسئلة سنوات سابقه لمادة الالكترونيات ل دكتور المادة حسام الناصر

Mark
50
: Al al-Bayt University
Faculty of Science
Department of Physics
Electronics (402331)
Final Exam
Monday 21/08/2006
(8:15-10:15)
Student Name:……………………………….Reg.No………………………Serial No………..
__________________________________________________ ____________________________
Encircle the correct answer:
1) A resistor and a capacitor are connected in series with a 1 KHz ac voltage source. If the impedance of the circuit is 100 Ω and the current in the circuit makes an angle of -30 0 with the voltage source, the value of the capacitance (in μF) and the resistance (in Ω) respectively are :
(a) 3.16, 86.7 (b) 1.58, 173.4 (c) 1.05, 260 (d) 0.6,390 (e) 0.79, 347
2) When the frequency of the voltage source applied to a series RL circuit is increased, the phase angle between the current and the voltage:
(a) increases (b) decreases (c) remains the same (d) becomes random
3) In the figure, if Vp=20V, the peak to peak current (in mA) in the circuit is:
(a) 81.2 (b) 101.5 (c) 19.1 (d) 40.6 (e) 61
4) For the series RLC circuit shown in the figure, if the resistance R=60Ω, the inductance L=79.6 mH , and the resonance frequency is 150Hz. The capacitive reactance Xc and the impedance (in Ω) at this frequency, respectively are:
(a) 50, 100 (b) 125, 80 (c) 75, 60 (d) 100, 40 (e) 25, 80
5) In the previous question, if the frequency of the ac voltage source changes such that the impedance of the circuit becomes 100Ω . The phase angle between the current and the voltage
( in degrees) is:
(a) 53.1 (b) 14 (c) 33.7 (d) 45 (e) 58.6
6) The purpose of trivalent impurity is to:
(a) reduce the conductivity of silicon (b) increase the number of holes
(c) increase the number of free electrons (d) create minority carriers
7) A silicon diode is in series with a 1 KΩ resistor and a 5V battery. If the anode of the diode is connected to the positive battery terminal, the voltage between the anode and the cathode is:
(a) 0.7 V (b) 0.3 V (c) 5.7 V (d) 4.3 V
8) When a 60 Hz sinusoidal voltage is applied to the input of a half-wave rectifier, the output frequency is:
(a) 120 Hz (b) 30 Hz (c) 60 Hz (d) 0 Hz
9) When the rms output voltage is 100 V, the PIV for each diode in a center-tapped full-wave rectifier is (neglecting the diode drop):
(a) 100 V (b) 200 V (c) 283 V (d) 50 V
10) The output voltage in the shown circuit is:
(a) half-wave rectified with Vp= -12.3 V
(b) half-wave rectified with Vp= -13 V
(c) full-wave rectified with Vp=-12.3 V
(d) full-wave rectified with Vp=-13 V
11) Determine the dc value of the output voltage in the shown circuit:
(a) 1.13 mV
(b) 103 mV
(c) 1.4 V
(d) 14.76 V
12) Determine the value of R in the shown circuit using the following data:
IZ=40 mA, VZT= 12.7V at IZT= 30mA,
ZZ= 30Ω
(a) 30Ω (b) 45.5Ω (c) 125Ω (d) 142.5Ω
13) A zener diode has an impedance of 15Ω. What is the output voltage at 50 mA if VZT = 4.7 V at IZT = 25mA?
(a) 5.075 V (b) 4.700 V (c) 0.750 V (d) 0.375 V
14) In a bipolar junction transistor, the emitter current is always:
(a) less than the base current (b) less than the collector current
(c) greater than the base current (d) equal the base current
15) Find VCE in the shown circuit?
(a) 1.13 V
(b) 5.1 V
(c) 1.4 V
(d) 11.5 V
16) Find IC in the shown circuit if αDC = 0.98?
(a) 1.27 mA
(b) 24.5 mA
(c) 45 μA
(d) 18 mA
17) Ideally, a dc load line is a straight line drawn on the collector characteristic curves between:
(a) the Q-point and cutoff (b) the Q-point and saturation
(c) VCE(Cut off) and IC(sat) (d) IB=0 and IB=IC/βDC
18) Find VCE in the shown circuit?
(a) 8.3 V
(b) 2.9 V
(c) 9.7 V
(d) 17.5 V
19) Find Ic in the shown circuit?
(a) 4.13 mA
(b) 5 mA
(c) zero
(d) 1.78 mA
20) Compared to a visible red light emitting diode (LED), an infrared LED
(a) produces light with longer wavelengths (b) produces light with shorter wavelengths
(c) produces only one color of light (d) produces light of all wavelengths

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