Basic Electronics AD/BS/BSIT University Of Sargodha (UOS) 2015

BS(T)

Subject: BSIT

University of Sargodha

Ist Term final Exam 2015

Course:Basic Electronics (PHY-2210)

Time Allowed: 2:30 Hours

Maximum Marks: 80

Note: Objective part is compulsory. Attempt any four questions from subjective parts.

Obiective Part

Q. 1 Write short answers of the following questions in 2-3 lines only

ustadni.. can a transfermer operate on De?

(16 x2 =

32)

*? What is avalanche Breakdown in reverse biased P-N Junction?

J. Define drift current in good conductor?

4. Define threshold voltage. Give its value for Si and Ge/Junction?

S. Why Collector-Base Junction is always reverse biased?

Which factors control the capacitance of the capacitor?

What is the basic principle behind the propagation of light in optical fibre?

%. Write down two examples of nonlinear resistor

7. Define Silicon Controlled Rectifier (SCR)?

кака

I Why electrons have greater mobility than holes in a semiconductor material?

ustadni.com

H. Mention at least five different energy sources

12. Briefly describe how electrons are multiplied in photomultiplier tube?

3. Draw symbols of an air-core and ad iron-core inductor?

4. Why we use series voltage dividers circuits?

J8. What is difference between electron and hole?

16. Do pure semiconductors obey Ohm's law?

Subjective Part (4 x 12 =

48)

0. 3(2)Discuss Capacitance of Capacitor in series and parallel connection?

(6)

Do Calculate the inductive reactance offered by a coil of inductance 250u to radio

frequency currents of frequencies

(i) 1MHz

(ii) 10MHz

Is Define parallel circuit? Explain characteristies of a parallel resistive circuit?

(б)

(6)

3120

6.02

In the circuit of Fig 1, Find

Fig 1

ustadni.com

Circuit current 2

Voltage of point A with respect to ground 41 2

it" Voltage ofpoint with respect to A - H7

Q. 4(a) Explain principle, construction, working and advantages of Bulk type photoconductive

9.S Define Optical Fibre? clasily Optical Fibes according to the way they propapaiekiblini.COm

96 Explain construction and working of fall wave rectifier using Centre tapped transformer.

Q. 7

A power transformer has 100 primary turns and 600 secondary turns. If primary voltage

is 120V and full load primary current is 12A, Find secondary

(i) Voltage V2

(ii) current I2

(4)

Draw a NPN Transistor circuit in common collector configuration and discuss its input.

output characteristics.

(12)

visit website bustad com