MCQs on Analog Electronics


Page 13 of 33. Go to page
01․ Secondary breakdown occures in
BJT but not is MOSFET.
Both BJT and MOSFET.
MOSFET but not in BJT.
None of these.

Secondary breakdown caused by a localized thermal runway, resulting from high current consideration. In case of BJT, the base current is sufficiently high in saturation region so that the collector - emitter voltage is low. Thus current is increased due to lower collector - emitter voltage. Hence secondary breakdown is occured in BJT.

02․ Common emitter current gain hFE of a BJT is
Always constant.
Dependent on base -emitter voltage.
Dependent on collector-emitter voltage.
Dependent on collector current.

Common emitter current gain is defined by the ratio collector current and the base current.

03․ The per unit impedance of a synchorous machine is 0.242. If base voltage is increased by 1.1 times, then per unit value will be
0.220.
0.200.
0.242.
0.266.

\[math] Base \; impedance \; = rac{(KV)^2}{(MVA)} [/math] [math] Z_{pu2} = Z_{pu1} rac{(KV_1)^2}{(KV_2)^2} = 0.242( rac{1}{1/10}^2 = 0.200[/math].

04․ When the pn junction is forward biased the sequence of events that take place are
diffusion, drift and recombination.
injection, diffusion and recombination.
diffusion, injection and drift.
none of above.

Under construction.

05․ The depletion region of a pn junction is one, that is depleted of
atoms.
mobiles charges.
immobile charges.
velocity of the carriers.

Under construction.

06․ The depletion region with in a pn junction is reduced when the junction has :
zero bias.
forward bias.
reverse bias.
all of these.

Under construction.

07․ A silicon pn junction in forward condition has a voltage drop closer to
0.1 V.
0.7 V.
1.7 V.
2.1 V.

Under construction.

08․ For a reverse biased pn junction, the electric current through the junction increases abruptly at
breakdown voltage.
0 V.
0.2 eV.
7.2 eV.

Under construction.

09․ The reverse saturation electric current of a pn junction varies with temperature (T) as
T.
1 / T.
independent of T.
T2.

Under construction.

10․ The transition capacitance of a reverse biased pn junction having uniform doping on both sides, varies with junction voltage ( VB ) as
1 / VB.
VB.
( VB )- 1 / 2.
( VB )2.

Under construction.

<<<1112131415>>>