Jawaharlal Nehru Technological University Kakinada 2007 B.Tech Electrical and Electronics Engineering PULSE AND DIGITAL CIRCUITS (2) - Question Paper

Code No: R059210202 Set No. 3
II B.Tech I Semester Regular Examinations, November 2007
PULSE AND DIGITAL CIRCUITS
( Common to Electrical & Electronic Engineering, Electronics &
Communication Engineering, Electronics & Instrumentation Engineering
and Electronics & Telematics)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
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1. (a) Verify V2= (V/2)(e2x
-1)/(e2x+1) = (V/2) tanhx for a symmetrical square
wave applied to a low pass RC circuit.
(b) Derive the expression for percentage tilt(P) of a square wave output of RC
high pass circuit. [8+8]
2. (a) provide the circuits of various kinds of shunt clippers and discuss their operation
with the help of their transfer characteristics.
(b) Draw the diode differentiator comparator circuit and discuss the operation of
it when ramp input signal is applied. [8+8]
3. Write Short notes on:
(a) Diode switching times
(b) Switching characteristics of transistors
(c) FET as a switch. [4+8+4]
4. (a) Draw the circuit diagram of a Schmitt trigger circuit and discuss its operation.
Derive the Expressions for its UTP and LTP.
(b) discuss how an Schmitt trigger circuit acts as a comparator. [12+4]
5. (a) discuss the basic principles of Miller and bootstrap time base generators.
(b) A transistor bootstrap ramp generator is to produce a 15V, 5ms output to a
2kohms load resistor. The ramp is to be linear within 2%. Design a suitable
circuit using Vcc = 22V, -VEE = -22V and transistor with hfe(min) = 25. The
input pulse has an amplitude of -5V, pulse width = 5ms and space width =
2.5ms. [8+8]
6. (a) What is relaxation oscillator? Name a few negative resistance devices used as
relaxation oscillators and provide its applications.
(b) With the help of a circuit diagram and waveforms, discuss the frequency
division by an astable multivibrator? [8+8]
7. (a) Why are sampling gates called linear gates?
(b) elaborate the other names of a gate signal?
(c) Compare the unidirectional and bi-directional sampling gates. [6+4+6]
1 of 2

8. (a) Why totem pole is used in DTL? Draw the circuit diagram and discuss a DTL
gate with this.
(b) Verify the truth table of RTL NOR gate with the circuit diagram of 2 inputs.
[8+8]
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Earning:   Approval pending.