2008 Anna University ECE - Electron Devices APRIL/MAY - 2008 Question paper

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2008 Anna University ECE - Electron Devices APRIL/MAY - 2008 Question paper

PART - A

1) .Write a note on dissipation factor

2). Give short notes on precision style wire wound resistor

3) .Give the equation for diode current in reverse bias condition

4) .Compare LED and LCD

5) .List the consequences of Early Effect

6) .Compare N channel FET and P channel FET

7) .What are the advantages of IC over discrete components

8 ) .Realize an IC having one capacitor, diode, transistor, and resistor

9). Give the structure of DIAC

10) .Write a note on LASCR

PART - B (5x16=80)

11) .(a) Discuss the motion of an electron under the influence of applied magnetic field (16)

OR

(b) .(i) Explain in detail about the magnetic deflection in CRT (10)

(ii) Compare electric and magnetic deflection systems (6)

12). (a) (i) Derive an expression for the total current under forward bias condition and reverse bias condition (10)

(ii) The diode current is 0.6 mA, when the applied voltage is 400 mV and 20 mA when the applied voltage is 500 mV. Determine 'eeta' . Assume KT/q=25mV (6)

OR

(b) .With a neat diagram and necessary waveforms explain the following circuits

(i) Positive Clipper (ii) Negative Clipper (iii) Biased Clipper (iv) Clamper (each 4)

13) .(a) Discuss in detail the input and output charecteristics of

(i) Common Base (5)

(ii) Common Emitter (5)

(iii) Common Collector (6)

And derive expressions for h(i),h(o),h(f),h(r).

OR

(b) (i) Derive an expression for voltage gain for an FET amplifier with CS and CD configuration (6)

(ii) Discuss in detail about the construction and working of Depletion MOSFET and Enhancement MOSFET (10)

14) .(a) With a neat diagram explain the following

(i) Silicon Wafer Preparation (4)

(ii) Oxide Growth (4)

(iii) Photolithography (8 )

OR

(b) Discuss in detail about

(i) Thin Film Fabrication (10)

(ii) Thick Film Fabrication (6)

15). (a) (i) With a neat diagram discuss in detail the structure, charecteristics and 2 transistor version of SCR (10)

(ii) Define

(1) Latching Current (1)

(2) Holding Current (2)

(3) GAte Current (1)

(4) Voltage safety factor (2)

OR

(b) (i) Discuss in detail the construction and charecteristics of UJT (8 )

(ii) Give the important application of UJT as relaxation oscillator (8 )