D 02000EC205092003 Pages: 2

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
Third Semester B.Tech Degree (S,FE) Examination December 2020 (2015 Scheme)

Course Code: EC205
Course Name: ELECTRONIC CIRCUITS (EC,AE)
Max. Marks: 100 Duration: 3 Hours
PARTA
Answer any two full questions, each carries 15 marks. Marks

1 a) Design and draw an RC differentiator circuit for a given input frequency of (4)
2KHz.
b) What are the functions of various capacitors used in RC coupled amplifier? (3)
c) Define stability factor. Derive an expression for the stability factor for leakage (8)
current of a voltage divider bias circuit. How does the voltage divider bias
improve the stability of an amplifier circuit?
2 a) With neat circuit diagrams, derive the design criteria for an RC circuit to function (8)
as

(i) Differentiator
(ii) Low pass filter
b) In the given circuit, Assume B=100, Vcc = 5 V, Veron = 0.7V, Re = 15 ಓಟ, (7)

Rpg = 650 KQ, ‏ع۷‎ = 2۷, Determine 100, (೧5೦. rt and gm. What will be the small

signal voltage gain? Assume values for parameters that are not given.

Vee

5

Ven ட

3 ஐ Explain the small signal hybrid pi model of transistor in the CE configuration (8)
with neat schematics. Derive the expression for voltage gain without bypass
capacitor.

b) For a voltage divider bias circuit using Vec=12V, Re = 2.2KQ, Re = 1.5 ಓಣ, (7)
R; = 7.2 1९९2, 1२2 = 2.2 KQ, र. = | KQ, draw AC and DC load lines and locate the

Q point. Assume values for parameters that are not given.

Page 1 of 2