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from the diagram. Energy gap of silicon is 1.11۷ and intrinsic carrier concentration is

1.5 x 10'°/cem?. (5)
(d) Explain the working of Tunnel diode. Draw its characteristics curve. (5)
5. (a) Derive Ideal diode equation. (10)

(b) Draw the electron and hole component of current in a forward biased PN junction.
Given that NuOR
6. (a) Explain the break down mechanisms occurred in abrupt PN junctions. (10)
(b) What is the depletion capacitance of a PN junction? Explain its variation with

reverse bias voltage. (5)
PART C
Question No. 7 is compulsory. Answer question No. 8 or 9

7. (a) Derive the expression for terminal currents of a transistor. (10)

(b) Draw the energy band diagram of a MOS capacitor in accumulation and in inversion

condition. (5)
(c) Explain the CV characteristics of a MOS capacitor (5)
8. (a) What are the mechanisms which cause base current in a transistor? (5)

(b) Draw the minority carrier distribution in PNP transistor during active mode. (5)

(c) Explain the amplification action of a transistor. (5)
(d) What is base width modulation? (5)
OR
9. (a) Explain the output characteristics of a MOSFET. (5)
(b) Derive the expression for drain current of MOSFET. (10)

(0) A silicon n channel MOSFET has »,=600cm 377-600, Cox=1.2 x 101 Fiem’,
W=S50um, L=10um and प्त =0.8 ४. Find the drain current when

(1). Ves=2V and Vps=1V

(11) Vgs=3 V and Vps=5V (5)

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