1 (a)
What are non-ideal effects in BJT? Explain any one non-ideal effect in BJT.

5 M

1 (b)
Determine the ideal reverse saturation current density in silicon p_N diode at 300°k Given Na=Nd=10

^{16}cm^{-3}, ni=1.5×10^{10}cm^{-3}
5 M

1 (c)
With neat diagram explain the operation of UJT relaxation oscillator.

5 M

1 (d)
Compare photo diode with phototransistor.

5 M

2 (a)
Draw energy band diagram of P-N Junction for zero, forward, reverse bias clearly showing junction diagram, depletion width, fermi energy level and barrier potential.

10 M

2 (b)
calculate the theoretical barrier height, built in potential barrier and maximum electric field in a metal semiconductor diode for zero applied bias consider a contact between tungsten and a type silicon doped to Nd=10

The metal work function for tungsten is ϕm=4.55V and electron a affinity for silicon is x=4.01V.

Nc=2.8×10

^{16}cm^{-3}at T=300k.The metal work function for tungsten is ϕm=4.55V and electron a affinity for silicon is x=4.01V.

Nc=2.8×10

^{19}cm^{-3}, K=1.38×10^{-23}J/K, εs=11.7×8.85×10^{-14}, e=1.6×10^{19}c.
10 M

3 (a)
Calculate the threshold voltage V

substrate doping density NA=10

_{TO}at V_{SB}for a polysilicon gate n channel MOS transistor with the following parameters-substrate doping density NA=10

^{16}cm^{-3}polysilicon gate doping density ND=2×10^{20}cm^{-3}gate oxide thickness tox=500A° oxide Interface fixed charge density NOX= 4×10^{10}cm^{-2}.
10 M

3 (b)
Derive the drain current equation ID for MOSFET in ohmic and saturation regions.

10 M

4 (a)
Draw and explain construction, working characteristics of JFET. Explain frequency limitation factors.

10 M

4 (b)
Explain schottky effect. Derive the position of maximum barrier Xm.

10 M

Draw and explain, Construction and working of:

5 (a) (i)
HEMT (MODFET)

5 M

5 (a) (ii)
MESFET

5 M

Explain basic structure and characteristics of:

5 (b) (i)
SCR

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5 (b) (ii)
DIAC

5 M

Solve any four of the following:

6 (a)
Draw and explain Ebers-moll model of transistor.

5 M

6 (b)
With the help of circuit diagram and characteristics explain application of zener diode as a voltage regulator.

5 M

6 (c)
What are optocouplers? Explain any one application of optocoupler.

5 M

6 (d)
Sketch and explain V-I and C-V characteristics of MOSFET.

5 M

6 (e)
Explain channel length modulation with cross section of MOSFET. Write equation associated with this effect.

5 M

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