JNTU previous papers | B-Tech I-Sem | Instrumentation components | November 2008


                                          (Electronics & Control Engineering)



1. (a) Explain the Basic principle of Mechanical Linkages.

(b) Illustrate a mechanical system using linkages.


2. (a) What is the importance of safely precautions in control system.

(b) List some methods of implementing safety measures in control system.

(c) Describe how values can be used to avoid failures in control system.


3. (a) Mention different types of potentiometers as applied to control systems.

(b) Describe the construction and working of a wire wound potentiometer.

(c) Mention important application of potentiometers.


4. (a) With a neat diagram explain the working of 3-? stepper motor.

(b) A three- phase variable stepper motor has the following parameters.

Average Phase winding Resistance = 1 ohm

Average phase winding Inductance = 30mH

Rated winding current = 3A.

Design a simple uni polar drive circuit, such that the electrical time constant

is 2 mSec at Phase turn-on and 1 mSec. At turn-off. The stepping rate is 300

steps per second.


5. (a) With neat sketches briefly explain the construction and working principle of varactor diode.

(b) What are the important specifications of varactor diode.


6. (a) Draw and explain the functional diagram of a 555 timer.

(b) What are the different modes of operation of a 555 timer? Explain the function

of reset.


7. (a) Explain the construction and working principle of photo detector.

(b) Describe how light dependent resistor is used for control applications?

(c) Explain how photodiode be use in a relay system.


8. (a) Explain how a prism is effectively used as a dispersing medium?

(b) Draw the cross sectional diagram of a diffraction grating. Explain.


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