JNTU Basic Electronics Question Paper November 2008

JNTU Basic Electronics Question Paper November 2008

(Mechanical Engineering, Production Engineering and Automobile Engineering)



1. (a) Draw and explain the energy band diagrams of conductor, semiconductor and insulator.

(b) Draw the V- I characteristics of an ideal diode. Distinguish between avalanche

and zener break down.


2. (a) Define the large signal current gain ? (in C B configuration) and ? (in CEconfiguration ) and obtain the relationship between them.

(b) How the SCR is used as a controlled rectifier. Explain with the help of necessary circuit diagram and wave forms.


3.(a) In RC coupled amplifier, the output voltage is 5V for a sinusoidal input of 5mV. Determine the voltage gain at mid band frequency and at half power frequencies.

(b) Draw the circuit diagram of current shunt feedback amplifier. Derive an expression for gain of circuit with and without feedback.

(c) What is the disadvantage of phase shift oscillator? How is this overcome in Wein Bridge Oscillator?


4. (a) Classify timers according to the function and briefly explain them.

(b) Draw the circuit for A.C. resistance welding and explain.


5. (a) Give the principle of Induction heating. What are the merits of Induction heating.

(b) Explain the application of Induction heating for

i. surface hardening of steel.

ii. Annealing of brass and iron.


6. (a) Discuss briefly

i. Eletrostatic focusing and

ii. Magnetostatic focusing methods used in cathode ray tube and compare their merits.

(b) Explain the need of ion trap in cathode ray tube.


7. (a) What is an interrupt? What are various interrupts? Explain them.

(b) Discuss about various fields in an instruction.


8. Explain the working principle of successive approximation A/D converter. Explain

the function of each block of the converter.

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