Basic Electronics ADP 1 Semester/Term University Of Sargodha (UOS) 2024

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University of Sargodha |

ADP 1" Term, pxamination 2024

Subject: LT Paper: Basic Electronics (PHYS-101

Time Allowed: 02:30 Hours Maximum Marks: 60

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

Objective Part (Compulsory)

0.1. Write short answers of the following in 2-3 [ines of each on your answer sheet. Se (2*12)

bg: Why equivalent capacitance is less than individual capacitance in the series combination?

ii. How does diode act as a switch? ‘ Vip £9

iii Why is silicon preferred over germanium ip the manufacture of semiconductor devices?

iv. Differentiate between Amplitude and frequency modulation.

v. Briefly explain the Photodiode.

vi. Define working principal of light emitting diode.

vii. Criticize this statement " if X; > X,. then we must have L > =."

viii. ~~ What is voltage divider rule?

ix. Write working principal of solar cell. ’

x. In NPN silicon transistor, @ = 0.995, 1; = 10 mA and leakage current Icgo = 0.5 pA. Determine

Icko- A

xi. We desire to make an LC circuit that oscillates at 100 Hz using and inductance of 2.5 H. What will

be the capacitance?

xii. Define dark current.

Subjective Part

49)

Q.2.

(a) What are different methods of biasing? Discuss volage divider bias. : (5)

(b) Find the «a rating of the transistor shown in Figure, Hence determine the value of lc using both

a and [} rating of the transistor. (4)

Ic

[y= 240 pA

— p=49

& Ig= 12 mA

Q.3.

(a) Explain the working of Transducers. Discuss its types in detail. (5)

(b) Each of the resistors in the diagram has a resistance of 12 Q. Find the total resistance. 4)

Q.4.

(a) Discuss the important properties of paramagnetic, diamagnetic, and ferromagnetic materials.

(b) A step-up transformer with 1: 10 ratio is connected to 22 V, 50 Hz AC supply mains.

(i) How

much is secondary voltage?

(ii) If secondary load is 100 ohms, what is the secondary current, and

primary current? Assume 100 % efficiency. (5+4)

Q.5. What is the difference between intrinsic and extrinsic semi-conductor materials? Explain the role

of doping of an impurity in a semi-conductor material. 9)

Q.6. Discuss the working of LED. What are the major factors that influence the brightness of the emitted

light?? What will be the effect when it is reverse biased?

9)

Q.7.

(a) What is voltage multiplier? Discuss working of half wave voltage doubler. (5)

(b) Draw transistor circuit configuration and determine the relation between a and B. (4)

mmmmmmsssem meee LK-6112/03-05-24 sommes