B.C.A-B.C.A Computer Application ELECTRONIC DEVICES AND DIGITAL CIRCUITS (Alagappa University - Directorate of Distance Education-2012)

DISTANCE EDUCATION
B.C.A. DEGREE EXAMINATION, MAY 2012.
ELECTRONIC DEVICES AND DIGITAL CIRCUITS
(2003 onwards)
Time : Three hours Maximum : 100 marks
Answer any FIVE questions.
All questions carry equal marks. (5 × 20 = 100)
1. (a) Explain in detail about BCD codes, Gray code, ASCII code with suitable example. (10)
(b) (i) Convert (1244)10 to ( ? )2 (3)
(ii) Convert (11101101101011)2 to ( )16 (3)
(iii) Convert (248)16 to ( )10. (4)
2. (a) Explain how the transistor acts as a switch. (10)
(b) Draw the logic symbol for AND, OR , NOT, and X-OR and give its truth table. (10)
3. (a) (i) Add (1111)2 and (0101)2
(ii) Find 2's complement of (1010101)2
(iii) Write the signed binary number for (+8)10
(iv) Subtract (0110)2 from (1011)2 . 10)
(b) Prove the following using De Morgan's theorem AB + CD = AB.CD (10)
4. (a) Draw the half subtractor logic circuit and explain it
with truth table. (10)
(b) Draw the three variable minterm karnaugh map
and explain how it is used for simplification. (10)
5. (a) (i) Draw R-S filp flop and give its truth table. (5)
(ii) Draw the D filp-flop and give the truth table. (5)
(b) Explain the function of 3-bit binary counter with truth table. (10)
6. (a) Draw the full adder logic circuit and explain it with truth table. (10)
(b) Briefly explain about Quine Mc kluskey tabulation method. (10)
7. (a) Explain working function and characteristics of a PN junction diode. (10)
(b) Explain the function of MOSFET. (10)
8. (a) Explain the function of a photodiode. (10)
(b) With a neat diagram explain the function of silicon control rectifier. (10)

Earning:  ₹ 6.50/-