Docstoc

Exam-7

Document Sample
Exam-7 Powered By Docstoc
					Islamic University of Gaza                                         Eng.Monther Abu Sultan
Faculty of Engineering                                             Eng. Alaa Abu Auda
Electrical Engineering Dept.                                       Fall 2011

Time allowed: 2Hours                 Electronic I         Date:9/1/2012
Total mark: 50                        Final Exam          Closed Book Exam
Student Name:                                             Student #:
Problem #1:     15 point
1. For the following clipper circuit
Assume the input vin(t) varying form -20 ≤vin(t)≤ 20,D1,D2 are Si Diodes
a) [5pts]Sketch transfer curve?
b) [2pts]What the rang of vin(t) that make Vout(t)=       vin(t) ?
c) [3pts]Assume the triangular voltage is applied to the input of clipper, sketch Vout(t)


                                                                                   -12



                                                                                      D2
                                                                       R1
                                                                                                     Vout(t)
                                                     Vin(t)
                                                                       2k
                                                                                                RL

                                                                                            1k
                                                                                      D1

                                                                                   -12
                                                                                            0




                                                                                   1|Page
2. For the following clamper circuit
The voltage signal vin(t) is applied to the input of clamper circuit
 [5pts]Sketch the voltage waveform Across the capacitor Vc?

                                                                                 10


                                                                                      D2

                                                                       +Vc-
                                                                                                    Vout(t)
                                                          Vin(t)
                                                                                               RL

                                                                                      D1   1k


                                                                                 -7
                                                                                           0




                                                                              2|Page
Problem #2:      15 point
For following common emitter amplifier, the transistor β =50, VBE=0.7v.
a) [4pts]Determine the Q-point for BJT transistor?
b) [2pt ]Draw AC equivalent circuit using re model?
c) [2pts]Drive the input impedance Zin,output impedance Zout?
d) [3pts]Drive the voltage gain            ?
e) [2pts]Drive the total voltage gain
f) [2pts]Assume Vsig=0.3sin(wt) mvolt
   i.  Sketch the total output voltage vout(t)
  ii. Sketch the total collector voltage vc(t)




                                                                          3|Page
Problem #3:      20 point
1. For the following combination network
a) [4pts]Determine the Dc voltages V1,V2?
b) [4pts]Determine the Q-point of each transistor?
c) [2pts]Sketch transfer curve for FET transistor?

                                                           +9v              +9v



                                                                 2.2k             2k


                                                                                  Beta=100
                                                                   V1
                                                                                       V2
                                                                 IDss=8mA
                                                                 Vp=-4v


                                                     10M                          0.5k
                                                                 0.750k




                                                                  4|Page
2. For the following Zener Diode circuit
   The operating currents of the zener diodes Z1 is 30 mA(Vz=10v) ,Z2 is 15mA(Vz=5v)
a) [5pts]Determine the values of limiting resistance R1,R2?
b) [5pts]Determine the lowest value of Vsupply for which the current through 500Ω
   is fixed ,when the operating current in Z1 is reduced to 5mA


                         R1                               R2


                                                          1k
             25v                           Vz=10v                          Vz=5v       500
                                           Z1                              Z2
          Vsupply




                                                                            5|Page

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:8
posted:2/6/2013
language:Unknown
pages:5