King Saud University Faculty. of Engineering
Electrical Engineering Dept. EE 318 2ed Mid Term Exam
17/11/1426 Time : 1 h
Question 1
Given that
w=1000 rad/sec
L = 10 mH
C1 = 100 mF
C2 = 10 mF
R = 100 W |
Find the equivalent impedance between a and b, then find the voltage across the resistor R both in magnitude and phase.
Question 2-a
If the input waveform is as shown in Fig..2 then draw the expected output waveform .
Question 2-b
For the transistor circuit shown in Fig 3
a- Find the Base current IB , collector current IC , and the collector voltage VCE . Is the transistor work in its active region .
b- If R2 is increased to 150 kW repeat part a and calculate the voltage gain Vo/Vi.
King Saud University Faculty of Engineering
Electrical Engineering Dept. EE 414 2ed mid term Exam
Question 1
Design a transistor Mixer , the transistor has b= 100 cm= 1 pF , Cp = 20 pF . The collector current IC is chosen such that 1< IC < 3 mA . Assume fRF = 1.6 MHz , fIF = 450 kHz the IF bandwidth must be 10 kHz L1 = 0.25 mH ,Qu = 200, RL = 50 W and is coupled to the collector circuit using a transformer with turns ratio np/ns = 10 . Draw the used circuit diagram and the ac equivalent circuit at the IF frequency.
Question 2
Design a class C power amplifier used in a transmitter working at 22 MHz with output power = 20 W .The load is 50 W and coupled to the collector circuit using transformer with primary inductance = 0.1 m H . The amplitude of the carrier signal is 8 V and the circuit efficiency has to be > 85% .
Define the following circuit component:
1- The dc power supply VCC 2- The biasing voltage
3- The output transformer turns ratio 4- The transistor output resistance .
5- The tuning capacitor
|
Irms/Idc |
Conduction Angle |
|
1.14 |
170 |
|
1.17 |
160 |
|
1.2 |
150 |
|
1.22 |
140 |
|
1.25 |
130 |
|
1.27 |
120 |
|
1.29 |
110 |