521 + Mcqs in Physical electronics devices and ics miscellaneous Page 8 McqOptions

351.	Increasing the collector supply voltage will increase
A.	Base current
B.	Collector current
C.	Emitter current
D.	None of these
Answer» E.

Discussion

352.	The transconductance gm of the transistor shown below in figure is 10 mS. The value of the input resistance R
A.	10 0 k
B.	8 3 k
C.	5 0 k
D.	2 5 k
Answer» D. 2 5 k

Discussion

353.	In a normally biased npn transistor, the electrons in the emitter have enough energy to overcome the barrier potential of the
A.	Base-emitter junction
B.	Base-collector junction
C.	Collector-base junction
D.	Recombination path
Answer» B. Base-collector junction

Discussion

354.	When a free electron recombines with a hole in the base region, the free electron becomes
A.	Another free electron
B.	A Valence electron
C.	A conduction-band electron
D.	A majority carrier
Answer» C. A conduction-band electron

Discussion

355.	The perfectly matched silicon transistors are connected as shown in figure below. The value of current I will be
A.	0 mA
B.	2 3 mA
C.	4 3 mA
D.	7 3 mA
Answer» D. 7 3 mA

Discussion

356.	Consider the transistor circuit given below. It is desired to have V
A.	1 k
B.	500
C.	2 k
D.	3 k
Answer» C. 2 k

Discussion

357.	In the active region, the collector current is not changed significantly by
A.	Base supply voltage
B.	Base current
C.	Current gain
D.	Collector resistance
Answer» D. Collector resistance

Discussion

358.	Consider the regulated power supply given below:
A.	25 3 V
B.	29 4 V
C.	27 8 V
D.	30 5 V
Answer» C. 27 8 V

Discussion

359.	The specification for a silicon transistor are: I
A.	92 ohms, 75 mhos
B.	40 ohms, 118 mhos
C.	12 5 ohms, 12 mhos
D.	112 ohms, 10 2 mhos
Answer» D. 112 ohms, 10 2 mhos

Discussion

360.	The common emitter amplifier shown in the figure below is biased using a 1 mA ideal current source. The approximate base current value is
A.	0 A
B.	10 A
C.	100 A
D.	1000 A
Answer» C. 100 A

Discussion

361.	AC emitter resistance equals 25 mV divided by the
A.	Quiescent base current
B.	DC emitter current
C.	AC emitter current
D.	Change in collector current
Answer» C. AC emitter current

Discussion

362.	The ac equivalent circuit is derived from the original circuit by shorting all
A.	Resistors
B.	Capacitors
C.	Inductors
D.	Transistors
Answer» C. Inductors

Discussion

363.	Reducing all dc sources to zero is one of the steps in getting the
A.	dc equivalent circuit
B.	ac equivalent circuit
C.	complete amplifier circuit
D.	voltage divider biasing circuit
Answer» C. complete amplifier circuit

Discussion

364.	The capacitors of a CE amplifier appear to be
A.	Open to ac
B.	Shorted to dc
C.	Open to supply voltage
D.	Shorted to ac
Answer» E.

Discussion

365.	The gain of a bipolar transistor drops at high frequencies. This is because of the
A.	Coupling and bypass capacitors
B.	Early effect
C.	Inter-electrode transistor capacitances
D.	Coupling and bypass capacitors, and interelectrode transistor capacitances
Answer» B. Early effect

Discussion

366.	The widths of the base in a GaAs transistor and in a Si transistor (both n-p-n type) are equal. GaAs transistor works at higher frequency
A.	The band gap of GaAs is higher than that of Si
B.	The base transit time is lower in GaAs
C.	The negative differential mobility in GaAs favours operational very high frequency
D.	Si transistor works at higher frequency compared to GaAs transistor
Answer» D. Si transistor works at higher frequency compared to GaAs transistor

Discussion

367.	In a transistor amplifier, the reverse saturation current I
A.	Doubled for every 10 C rise in temperature
B.	Doubled for every 1 C rise in temperature
C.	Increased linearly with temperature
D.	Doubled for every 5 C rise in temperature
Answer» B. Doubled for every 1 C rise in temperature

Discussion

368.	From a measurement of the rise time of the output pulse on an amplifier whose input is a small amplitude square wave, one can estimate which of the following parameter of the amplifier?
A.	Gain bandwidth product
B.	Slew rate
C.	Upper 3-dB frequency
D.	Lower 3-dB frequency
Answer» D. Lower 3-dB frequency

Discussion

369.	The phase difference between the input and output voltages in a common base arrangement is
A.	180
B.	90
C.	270
D.	0
Answer» E.

Discussion

370.	Most of the majority carriers from emitter
A.	Recombine in the base
B.	Recombine in the emitter
C.	Pass through the base region to the collector
D.	None of the above
Answer» D. None of the above

Discussion

371.	At the base emitter junction of a transistor, one finds
A.	Reverse bias
B.	A wide depletion layer
C.	Low resistance
D.	None of these
Answer» D. None of these

Discussion

372.	In a p-n-p transistor, current carriers are
A.	Acceptor ions
B.	Donor ions
C.	Free electrons
D.	Holes
Answer» E.

Discussion

373.	In a p-n-p transistor, in the base region, the main stream of current is
A.	Drift of holes
B.	Diffusion of holes
C.	Drift of electrons
D.	Diffusion of electrons
Answer» C. Drift of electrons

Discussion

374.	The device associated with voltage-controlled capacitance is a
A.	Light emitting diode
B.	Photodiode
C.	Varactor diode
D.	Zener diode
Answer» D. Zener diode

Discussion

375.	The conductivity of the emitter region of a BJT is kept
A.	Same as that of base region
B.	Much larger than that of base region
C.	Same as that of collector region
D.	Much smaller than that of base region
Answer» D. Much smaller than that of base region

Discussion

376.	The current through the zener diode in figure given below is
A.	0 mA
B.	3 3A
C.	2 mA
D.	20 mA
Answer» D. 20 mA

Discussion

377.	In a transistor if = 0.9, will be equal to
A.	1.0
B.	0.09
C.	0.90
D.	9.0
Answer» E.

Discussion

378.	The arrow on the emitter of a transistor indicates
A.	The direction of electron flow
B.	The direction of displacement current
C.	The direction of conventional current flow
D.	The ground connections
Answer» D. The ground connections

Discussion

379.	Introducing a resistor in the emitter of a common amplifier stabilizers the dc operating point against variation is
A.	Only the temperature
B.	Only the of the transistor
C.	Both temperature and
D.	None of above
Answer» D. None of above

Discussion

380.	A transistor is said to be in quiescent state when
A.	No signal is applied to the input
B.	It is unbiased
C.	No currents are flowing
D.	Emitter junction bias is just equal to collector junction bias
Answer» B. It is unbiased

Discussion

381.	A BJT is said to be operated in the saturated region if
A.	Both the junctions are reverse biased
B.	Base-emitter junction is reverse biased and base-collector is forward biased
C.	Both junctions are forward biased
D.	None of these
Answer» D. None of these

Discussion

382.	Which is the most heavily doped region in a transistor?
A.	Emitter
B.	Collector
C.	Base
D.	All regions are equally doped
Answer» B. Collector

Discussion

383.	n-p-n transistors prefered over p-n-p
A.	npn transistor is smaller in area
B.	Mobility of electron is higher than the hole
C.	Mobility of hole electron is higher than the hole electron
D.	None of the above
Answer» C. Mobility of hole electron is higher than the hole electron

Discussion

384.	For the circuit shown in figure the value of I
A.	400 A
B.	400 A
C.	600 A
D.	600 A
Answer» C. 600 A

Discussion

385.	For a transistor, the current gain relation between CB current gain a and CE current gain b is
A.	= (1 )
B.	<table><tr><td rowspan="2"> = </td> <td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> </center></td></tr><td align="center">1 </td></table>
C.	= (1 + )
D.	= (1 + )
Answer» B. <table><tr><td rowspan="2"> = </td> <td style="border-bottom:1px solid #000000;vertical-align:bottom;padding-bottom:2px;"><center> </center></td></tr><td align="center">1 </td></table>

Discussion

386.	For a transistor = 40 and I
A.	1 mA
B.	0.975 mA
C.	1.025 mA
D.	None of these
Answer» D. None of these

Discussion

387.	The region of operation of the transistor in the circuit below is
A.	Forward-active
B.	Reverse-active
C.	Saturation
D.	Cut-off
Answer» C. Saturation

Discussion

388.	Most of the transistors are npn type and not pnp type because
A.	npn transistor gives large voltage gain
B.	npn transistors a more negative than pnp transistors
C.	In transistor, the current conduction is by free electrons which are less mobile than holes
D.	We can have high conduction in npn transistors.
Answer» E.

Discussion

389.	The highest area in a transistor
A.	Emitter
B.	Base
C.	Collector
D.	All
Answer» D. All

Discussion

390.	When the light increases, the reverse minority carrier current in a photodiode
A.	Decreases
B.	Increases
C.	Is unaffected
D.	Reverse direction
Answer» C. Is unaffected

Discussion

391.	The most noticeable effect of a small increase in temperature in the common emitter connected transistor is
A.	The increase in the ac current gain
B.	The decrease in the ac current gain
C.	The increase in output resistance
D.	The increase in I
E.	<sub>CEO </sub>
Answer» E. <sub>CEO </sub>

Discussion

392.	For above question I
A.	1 pA
B.	2 pA
C.	3 pA
D.	50 pA
Answer» B. 2 pA

Discussion

393.	When determining the common-emitter current gain by making small changes in direct currents, the collector voltage is held constant so that
A.	The output resistance will be high
B.	The transistor will not burn out
C.	The change in emitter current will be due to a change in collector current
D.	The change in collector current will be due to a change in base current
Answer» E.

Discussion

394.	cut-off frequency of a bipolar junction transistor increases with the
A.	Increase in base width
B.	Increase in emitter width
C.	Increase in the collector width
D.	Decrease in the base width
Answer» B. Increase in emitter width

Discussion

395.	A photodiode is normally
A.	Forward-biased
B.	Reverse-biased
C.	Neither-forward-nor reverse-biased
D.	Emitting light
Answer» C. Neither-forward-nor reverse-biased

Discussion

396.	The number of depletion layers in a transistor is
A.	Four
B.	Three
C.	One
D.	Two
Answer» E.

Discussion

397.	Breakdown does not destroy a zener diode, provided the zener current is less than the
A.	Breakdown voltage
B.	Zener test current
C.	Maximum zener current rating
D.	Barrier potential
Answer» D. Barrier potential

Discussion

398.	Under high electric fields, in a semiconductor increasing electric field
A.	1 and 4 only
B.	1 and 3 only
C.	All of the above
D.	None of these
Answer» C. All of the above

Discussion

399.	When the zener voltage increases in a zener regulator, which of these currents remains approximately constant?
A.	Series current
B.	Zener current
C.	Load current
D.	Total current
Answer» E.

Discussion

400.	Reverse recovery current in a diode depends upon
A.	Forward field current
B.	Storage charge
C.	Temperature
D.	PIV
Answer» B. Storage charge

Discussion

Explore topic-wise MCQs in Physical Electronics Devices and ICs.

Increasing the collector supply voltage will increase

The transconductance gm of the transistor shown below in figure is 10 mS. The value of the input resistance R

In a normally biased npn transistor, the electrons in the emitter have enough energy to overcome the barrier potential of the

When a free electron recombines with a hole in the base region, the free electron becomes

The perfectly matched silicon transistors are connected as shown in figure below. The value of current I will be

Consider the transistor circuit given below. It is desired to have V

In the active region, the collector current is not changed significantly by

Consider the regulated power supply given below:

The specification for a silicon transistor are: I

The common emitter amplifier shown in the figure below is biased using a 1 mA ideal current source. The approximate base current value is

AC emitter resistance equals 25 mV divided by the

The ac equivalent circuit is derived from the original circuit by shorting all

Reducing all dc sources to zero is one of the steps in getting the

The capacitors of a CE amplifier appear to be

The gain of a bipolar transistor drops at high frequencies. This is because of the

The widths of the base in a GaAs transistor and in a Si transistor (both n-p-n type) are equal. GaAs transistor works at higher frequency

In a transistor amplifier, the reverse saturation current I

From a measurement of the rise time of the output pulse on an amplifier whose input is a small amplitude square wave, one can estimate which of the following parameter of the amplifier?

The phase difference between the input and output voltages in a common base arrangement is

Most of the majority carriers from emitter

At the base emitter junction of a transistor, one finds

In a p-n-p transistor, current carriers are

In a p-n-p transistor, in the base region, the main stream of current is

The device associated with voltage-controlled capacitance is a

The conductivity of the emitter region of a BJT is kept

The current through the zener diode in figure given below is

In a transistor if = 0.9, will be equal to

The arrow on the emitter of a transistor indicates

Introducing a resistor in the emitter of a common amplifier stabilizers the dc operating point against variation is

A transistor is said to be in quiescent state when

A BJT is said to be operated in the saturated region if

Which is the most heavily doped region in a transistor?

n-p-n transistors prefered over p-n-p

For the circuit shown in figure the value of I

For a transistor, the current gain relation between CB current gain a and CE current gain b is

For a transistor = 40 and I

The region of operation of the transistor in the circuit below is

Most of the transistors are npn type and not pnp type because

The highest area in a transistor

When the light increases, the reverse minority carrier current in a photodiode

The most noticeable effect of a small increase in temperature in the common emitter connected transistor is

For above question I

When determining the common-emitter current gain by making small changes in direct currents, the collector voltage is held constant so that

cut-off frequency of a bipolar junction transistor increases with the

A photodiode is normally

The number of depletion layers in a transistor is

Breakdown does not destroy a zener diode, provided the zener current is less than the

Under high electric fields, in a semiconductor increasing electric field

When the zener voltage increases in a zener regulator, which of these currents remains approximately constant?

Reverse recovery current in a diode depends upon