Download Electronics 2(1) - Philadelphia University Jordan

Philadelphia University
Faculty of Engineering
Student Name:
Student Number:
Dept. of Communications and Electronics Engineering
Final Exam,
Course Title: Electronics 2
Course No: 650342
Lecturer: Dr. Wagah F. Mohammad
Section: 1
Question 1:
This question is general: Choose (√) the correct answer.
1- One of the following Transistor configurations is suitable for power amplifier:
 Common emitter configuration.
 Common collector configuration.
 Common base configuration.
2- One of the following Transistor configurations has good frequency response:
 Common emitter configuration.
 Common collector configuration.
 Common base configuration.
4- The total voltage gains of an amplifier having input resistance Rin and the signal source
resistance Rs; will be higher if:
 Rs > Rin.
 Rs= 0.
 Rs = Rin.
5- The output resistance (Rout) of Darlington pair configuration of βD and input resistance rπ is
equal to:
 Rout= βD rπ.
 Rout= βD / rπ.
 Rout= rπ / βD.
6- The total voltage gain of cascode
BiCMOS amplifier is equal to:
I
Vout
 gm1β2ro2.
Vbias
T2(BJT)
 gm1gm2ro1.
 gm1gm2ro2.
Vin
T1(MOS)
7- The OP AMP is connected as:
 Integrator.
 Differentiator.
 Active filter.
8- Power amplifiers are characterized by small output:
 Resistance.
 Power.
 Current.
Vin
_
OP
+
R
C
Vout
9- Crossover distortion in class B amplifier occurs when the transistors are:
 One is off and the other is on.
 Both transistors are on.
 Both transistors are off.
10- 0.7Av is chosen to be the gain at cutoff frequency because the power dropped to:
 P= 0.7 Pmid.
 P= 0.5 Pmid.
 Zero.
11- The miller effect input capacitance (Cm) appears at high frequency will increase the
input capacitance by:
 Cm = Av Cin
 Cm = (1-Av)Cin
 Cm = (1/Av)Cin
Question 2:
(8Marks)
Choose (√) the correct answer
1- The total current gain of the electronic system shown in the figure is:
 Ai = 25
Avnl=
 A i= 100
AC 4R
V
100 R out
 Ai = 400
2- The total voltage gain of the electronic system shown in the figure is equal to:
 Avt = 25
R
R
Avnl=
 Avt = 100
AC 2R
100 3R Vout
 Avt = 400
3- The differential gain of the differential
amplifier is equal to:
 Avd = 100
 Avd = 200
 Avd = 400
Vcc=20V
10 KΩ
Vdin
T1
50Ω
100K
10 KΩ
Vdout
T2
50Ω
I=1mA
4- The common mode gain of the differential amplifier shown in the above figure is equal to:
 Avcm = 0.2.
 Avcm = 0.1.
 Avcm = 0.05.
Question 3:
Draw the circuit diagram of a two-pole high-pass Butterworth filter. Calculate the values of R3
and R4 of the filter to be used for radio amplifier application of bandwidth 1 MHz . Suppose
C1=C2= 10 PF.
Question 4:
Class AB power amplifier consist of two
transistors is biased with 10μA DC Base
current and 10 mA peak base current.
SupposeVbe=0.75V, Vt=25mV and β= 50
of the transistors, calculate: 1- The output
resistance of this amplifier. 2-power
delivered to 4 Ω load resistor, the power
supplied to the amplifier and the efficiency
of the amplifier.
I1
R1
Vin
T1 IO
R3
Vout
T2
R2
RL=4 Ω
I2
-Vcc=-10 V
RB= 500KΩ
Question 5
Determine fHi, fHo, fβ and ft of the amplifier
shown in the figure. Suppose βmid=100,
Vbe=0.7 V, Vt= 25mV, Cbe=30pF, Cbc=5
pF and Cce= 1pF. Ignore ro, Cwin and Cwout.
Vcc=+10 V
Vcc =12V
IC
IB
Rc=2KΩ
Vout
Cbc
IE
RL=2KΩ
Cce
Cbe
Good luck