Osmania University (OU) 2006-2nd Sem B.E Electronics & Tele-Communication Engineering 2/4 (E.C.E)(ESTER)SUPPLEMENTARY ,IL, Pulse, digital and switching circuits - Question Paper
B.E 2/4 (E.C.E)(II-SEMESTER)SUPPLEMENTARY EXAMINATION,APRIL,2006
Pulse, digital and switching circuits
Code No.: 10049
FACULTY OF ENGINEERING B.E. ll/TV Year (ECE) n Semester (Main) Examination, April 2006
PULSE, DIGITAL AND SWITCHING CIRCUTTS Time : 3 Hours] [Max. Marks : 75
Ansu>er all questions of Part A and any five questions from Part B.
Fart A - (Marks : 25)
1. Show the circuit for the compensated attenuator and state the condition for perfect attenuation. 3
2. State Clamping theorem. What is its significance? 2
3. What is the role of commuting capacitors in a binary circuit? 2
4. State the applications of UJT relaxation oscillator. 3
5. What is meant by essential prime implicant? 1
6. Prove the following Boolean algebra theorem.
A +BC= (A + B) (A + C) 2
7. Make a K-map for the following function.
f - AB + AC + C + AD + ABC + ABC. 4
8. Draw the logic diagram of Binary to BCD code converter using 4 bit MSI adder and other hardware. 3
9. Realize T Flip-flop using D Flip-flop. 2
10. What is the maximum frequency of operation of a 4 bit asynchronous binary counter, if the propagation delay of each flip-flop is 25 ns? 3
Part B - (Marks : 5 x 10 = 50)
11. (a) Draw a circuit for clipping at two independent levels and explain its operation
with the help of its transfer characteristics. 4
(b) A symmetrical 10 kHz square wave of amplitude 10V is impressed upon a diode clamping circuit, shown below. Calculate and plot the output under steady state conditions. Assume for the diode VD_ = OV, r, = 100 ohms and r = <*>. 6
dL I i
lkQ lfif O-WvW-11
-o +
10k v0
o -
O-
12. Design a Schmitt trigger circuit for VTP = 6V and LTP = 3V. Assume Vcc = 15V. Use NPN transistors, haWng-I, = lOOWA, = 50, VCE(sa0 = OV. VBE(sat) = 0,7V, VBE (actlve) =0.6 V. Show the circuit diagram with all component values and explain its operation with the help of its transfer characteristic. 10
13. (a) Determine the canonical sum of products representation of the function :
fix, y, z) = x + {xy + xz) 3
(b) Using K map, determine minimum sum of products for the following function. f(V'W,x,y,z} = Im (0,.2, 3, 4, 5, II, 18, 19, 20, 23, 24, 28, 29, 31) 7
14. (a) Write about identification of symmetric functions. 6 (b) Realize full adder using minimum number of NAND gates. 4
15. Design a decade up counter using D Flip-flops. 10
16. (a) Design a binary to gray code converter. 7
(b) Prove that for any periodic input, the average value of output of a RC high pars circuit is equal to zero. 3
17. Write any two of the following : 2 x 5 =10
(a) Quine-Mc Cluskey method
(b) Turn off-methods of SCR
(c) Hazard free logic design
(d) Draw and explain the operation of astable multivibrator circuit using NPN transistors.
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