Paper/subject Code: 40902/ Electronic device and circuits – II

Q.P. Code: 37284 [Time: 3 Hours] [Marks: 80]

Please check whether you have got the right question paper.

N.B. 1. Q.1 is compulsory.

1. Solve any three questions Q.2 to Q.6

2. Assume suitable data

3. Write any four (20) a) Explain high frequency equivalent circuit of BJT b) Explain barkhausen criteria c) Draw MOSFET differential amplifier with active load d) Calculate max. power dissipation with and without heatsink

$\theta$jc = 1.75c° c/w, $\theta$cs , $\theta$_ca = 50° c/w

$\theta$_sa = 5° c/w . $t_jmax$ = 150° c and $t_amb$ = 30° C

e) Explain PNPN diode.

1. A) Explain class B push pull power amplifier and cross over distortion also derive expression for efficiency (10)

b) explain small signal analysis for MOSFET active load circuit (10)

1. (a) calculate lower cut off frequency for given circuit (10)

$\beta$ = 80, $r_\pi$ = 1.3 k$\Omega$, $g_m2$ = 50$\mu$ A/V, $c_\pi$ = 15 pf, c$\mu$ = 1pf (10)

b) explain working of SCR with V-1 characteristics and its applications (10)

1. a) explain Hartley oscillator. Design the same for 50KHz (10)

Paper/subject code: 40902 / Electronic Device and Circuits – II

Q.P. Code: 37284

b) find $i_q$ for given circuit (10)

$k_n1$ = $k_n2$ = 0.1 ma/$v^2$ , $k_n3$ = $k_n4$ = 0.3ma/$v^2$, $v_tn$ = 1 v,

$\lambda$ = 0 for $m_1$ $m_2$ $m_3$ and $\lambda$ = 0.01/v for $m_4$

a) Calculate bandwidth for two stages RC coupled CE amplifier. (10)

$\beta_1$ = 100, $\beta_2$ = 150, $r_\pi$ = $r_\pi2$ = 1.3 K$\Omega$ , $g_m1$ = $g_m2$ = 50A/V

$c_\pi1$ = $c_\pi2$ = 15 pf, c $\mu_1$ = c $\mu_2$ = 1 pf.

b) Explain feedback topologies with the help of neat block diagram. (10)

Solve any three (20)

a) Cascode MOSFET amplifier

b) UJT relaxation oscillator

c) Darlington configuration

d) Power BJTs