In a semiconductor diode, the cut-in voltage is the voltage:

at which the current is 10% of the maximum rated current

upto which the current is very small

at which the current is 10% of the maximum rated current

at which the depletion layer is formed.

Direction: Given question consists of two statements, one labeled as the 'Assertion (A)' and the other as 'Reason (R)'. You are to examine these two statements carefully and select the answers to these items using the codes given below.Assertion (A): A tunnel diode has an extremely thin depletion layer.Reason (R): Tunneling phenomenon occurs when a very heavily doped junction is reverse biased.

Both A and R are individually true but R is NOT the correct explanation of A

Both A and R are individually true and R is the correct explanation of A

Both A and R are individually true but R is NOT the correct explanation of A

A zener diode, when used in voltage stabilization circuits, is biased in

Reverse bias region below the breakdown voltage

Forward bias constant current mode

In an abrupt p-n junction if NA ≪ ND, then the barrier potential is:1) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}W\)2) \(\frac{{q{N_A}}}{{2{\epsilon_S}}}{W^2}\)3) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}{W^2}\)4) \(\frac{{q\left( {{N_A}} \right)}}{{2{\epsilon_S}}}W\)of these statements:

(3) is correct but (1) is wrong

(1) is correct but (3) is wrong

(2) is correct but (4) is wrong

(3) is correct but (1) is wrong

(4) is correct but (2) is wrong

Directions: The following items consist of two statements, one labeled as “Assertion(A)” and the other labeled as “Reason(R)”. You are to examine the two statements carefully and decide if the Assertion(A) and the Reason(R) are individually true and if so whether the reason is a correct explanation of the assertion. Select your answer to these items using the codes given below and mark your answer accordingly.Assertion (A): In a p-n junction the electron crossing the junction from right to left constitutes a current in the same direction as hole crossing the junction from left to right.Reason (R): In a p-n junction the low value of depletion region capacitance can be obtained with reverse biasing.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true, but (R) is not the correct explanation of (A).

A voltage regulator is used in:

Providing constant power supply to computers

Match List-I with List-II and select the correct answer using the codes given below the lists:List – IList – II (A) At peak point1. Low tunneling current(B) At valley point2. Zero tunneling current(C) Reverse bias region3. High diffusion current(D) Beyond valley point4. High tunneling current

(A) - (1), (B) - (2), (C) - (4), (D) - (3)

(A) - (3), (B) - (2), (C) - (4), (D) - (1)

(A) - (1), (B) - (2), (C) - (4), (D) - (3)

(A) - (3), (B) - (4), (C) - (2), (D) - (1)

(A) - (1), (B) - (4), (C) - (2), (D) - (3)

In a p-n diode, holes diffuse from p-region to n-region because

There is higher concentration of holes in the p-region

Holes are urged to move by the barrier potential

Free-electron in the n-region attract the holes

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)Assertion (A): In Gunn effect, when electric field is varied from zero to a threshold value. The drift velocity decreasesReason (R): Beyond the threshold electric field, if the electric field is increased. The drift velocity is decreased and the diode exhibits negative resistance.In the light of the above statement, choose the most appropriate answer from the options given below:

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Both (A) and (R) are correct and (R) is the correct explanation of (A)

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

(A) is correct but (R) is not correct

(A) is not correct but (R) is correct

Consider avalanche breakdown in a silicon \(\rm p^+n\) junction. The n-region is uniformly doped with a donor density \(\rm N_D\). Assume that breakdown occurs when the magnitude of the electric field at any point in the device becomes equal to the critical field \(\rm E_{crit}\). Assume \(\rm E_{crit}\) to be independent of \(\rm N_D\). If the built-in voltage of the \(\rm p^+n\) junction is much smaller than the breakdown voltage, \(\rm V_{BR}\), the relationship between \(\rm V_{BR}\) and \(\rm N_D\) is given by

\({{\rm{N}}_{\rm{D}}}/{{\rm{V}}_{{\rm{BR}}}}\) constant

\({{\rm{V}}_{{\rm{BR}}}} \times \sqrt {{{\rm{N}}_{\rm{D}}}}\) constant

\({{\rm{N}}_{\rm{D}}} \times \sqrt {{{\rm{V}}_{{\rm{BR}}}}}\) constant

\({{\rm{N}}_{\rm{D}}} \times {{\rm{V}}_{{\rm{BR}}}}\) constant

\({{\rm{N}}_{\rm{D}}}/{{\rm{V}}_{{\rm{BR}}}}\) constant

How does the dynamic resistance of diode vary with temperature?

Directly to the square of temperature

A zener diode works on the principle of

tunneling of charge carriers across the junction

diffusion of charge carriers across the junction

hopping of charge carriers across the junction

In a p+n junction diode under reverse bias, the magnitude of electric field is maximum at

The centre of the depletion region on the n – side

The edge of the depletion region of the p – side

The edge of the depletion region on the n – side

The centre of the depletion region on the n – side

For a silicon diode, the value of the forward bias voltage typically:

depends on the width of the depletion region.

depends on the concentration of the majority carriers.

As compared to a full-wave rectifier using two diodes, the four diode bridge rectifier has the dominant advantage of __________.

Higher current carrying capacity

lower peak inverse voltage requirement

In a forward biased region of a pn junction diode

the diode current decreases exponentially with decrease in voltage

the diode current increases exponentially with decrease in voltage

the diode current decreases exponentially with increase in voltage

the diode current increases exponentially with increase in voltage

the diode current decreases exponentially with decrease in voltage

In Gunn diodes, electrons are transferred from

Low to high mobility energy bands

High to low mobility energy bands

Low to high mobility energy bands

Diode is a unilateral circuit element because

it is unsymmetrical in fabrication

it can conduct current in both directions

it conducts current in only one direction

it is unsymmetrical in fabrication

In a pn junction diode under reverse bias, the magnitude of electric field is a maximum at

The edge of the depletion region on the p-side

The edge of the depletion region on the n-side

Match List I with List II and select the correct answer using the code given below the lists: List I List IIA.Tuned circuits1.Schottky diodeB.Voltage reference2.Varactor diodeC.High-frequency switch3.PIN diodeD.Current controlled attenuator4.Zener diode

A – 3, B – 4, C – 1, D - 2

A – 2, B – 4, C – 1, D - 3

A – 3, B – 4, C – 1, D - 2

A – 2, B – 1, C – 4, D - 3

A – 3, C – 1, D – 4, D - 2

Match List I with List IIList I(Volt-ampere characteristics of tunnel diode)List II(Observation)(a) At peak current Ip corresponding to Vp(i) Resistance becomes and remains positive(b) If voltage increase beyond Vp(ii) Current reaches Ip (peak current) and increase(c) When voltage is just more than valley voltage(iii) \(\frac{dI}{dV}\) is negative(d) when voltage is more than peak forward voltage(iv) Slope \(\frac{dI}{dV}\) is zero Choose the correct answer from the option given below:

(a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)

(a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)

(a) - (iv), (b) - (iii), (c) - (i), (d) - (ii)

(a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)

(a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)

93 + Mcqs in Pn Junction Diode in Electronic Devices Circuits Page 1 McqOptions

1.	What will be the output of the following circuit? (Assume 0.7V drop across the diode)
A.	12V
B.	12.7V
C.	11.3V
D.	0V
E.	a) 12Vb) 12.7Vc) 11.3Vd) 0V
Answer» D. 0V

Discussion

2.	When the diode is reverse biased with a voltage of 6V and Vbi=0.63V. Calculate the total potential.
A.	6V
B.	6.63V
C.	5.27V
D.	0.63V
Answer» C. 5.27V

Discussion

3.	What is the maximum electric field when Vbi=2V , VR=5V and width of the semiconductor is 7cm?
A.	-100V/m
B.	-200V/m
C.	100V/m
D.	200V/m
Answer» C. 100V/m

Discussion

4.	If the voltage of the potential barrier is V0. A voltage V is applied to the input, at what moment will the barrier disappear?
A.	V< V0
B.	V= V0
C.	V> V0
D.	V<< V0
Answer» C. V> V0

Discussion

5.	A TRAPATT diode has the following parameters:Doping concentration = 2 × 1015cm−3Current density = 20 KA/cm2The avalanche zone velocity of carriers is given by:
A.	2.25 × 105 m/s
B.	6.25×107 cm/s
C.	6.25×103 m/s
D.	2.35×108 m/s
Answer» C. 6.25×103 m/s

Discussion

6.	In a semiconductor diode, the cut-in voltage is the voltage:
A.	upto which the current is zero
B.	upto which the current is very small
C.	at which the current is 10% of the maximum rated current
D.	at which the depletion layer is formed.
Answer» C. at which the current is 10% of the maximum rated current

Discussion

7.	Direction: Given question consists of two statements, one labeled as the 'Assertion (A)' and the other as 'Reason (R)'. You are to examine these two statements carefully and select the answers to these items using the codes given below.Assertion (A): A tunnel diode has an extremely thin depletion layer.Reason (R): Tunneling phenomenon occurs when a very heavily doped junction is reverse biased.
A.	Both A and R are individually true and R is the correct explanation of A
B.	Both A and R are individually true but R is NOT the correct explanation of A
C.	A is true but R is false
D.	A is false but R is true
Answer» B. Both A and R are individually true but R is NOT the correct explanation of A

Discussion

8.	In a p-n diode, with the increase reverse bias, the reverse current
A.	Increases
B.	decreases
C.	remain constant
D.	uncertain
Answer» D. uncertain

Discussion

9.	A zener diode, when used in voltage stabilization circuits, is biased in
A.	Reverse bias region below the breakdown voltage
B.	Reverse breakdown region
C.	Forward bias region
D.	Forward bias constant current mode
Answer» C. Forward bias region

Discussion

10.	Match the following:a) Ambipolar Diffusion Constanti) \(\sqrt {\frac{{{\mu _n}{D_n}}}{{{\mu _p}{D_p}}}} \)b) Ambipolar Diffusion Constant of the excess carriersii) \(\frac{{\left( {n + p} \right){D_n}{D_p}}}{{n{D_n} + p{D_p}}}\)c) Diffusion Constant for holesiii) \(\frac{{2{D_n}{D_p}}}{{{D_n} + {D_p}}}\) d) Constant γiv) \(\frac{{{D_a}\left( {1 + \gamma } \right)}}{{2\gamma }}\)Code:
A.	a-ii, b-iii, c-iv, d-i
B.	a-i, b-ii, c-iii, d-iv
C.	a-iii, b-iv, c-i, d-ii
D.	a-iv, b-i, c-ii, d-iii
Answer» B. a-i, b-ii, c-iii, d-iv

Discussion

11.	In an abrupt p-n junction if NA ≪ ND, then the barrier potential is:1) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}W\)2) \(\frac{{q{N_A}}}{{2{\epsilon_S}}}{W^2}\)3) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}{W^2}\)4) \(\frac{{q\left( {{N_A}} \right)}}{{2{\epsilon_S}}}W\)of these statements:
A.	(1) is correct but (3) is wrong
B.	(2) is correct but (4) is wrong
C.	(3) is correct but (1) is wrong
D.	(4) is correct but (2) is wrong
Answer» C. (3) is correct but (1) is wrong

Discussion

12.	In the circuit shown below if the input voltage increases, which current remains practically constant?
A.	IT
B.	IZ
C.	IL
D.	All of the above
Answer» D. All of the above

Discussion

13.	Diffusion capacitance is present in:
A.	unbiased p-n diode
B.	reverse-biased zener diode
C.	forward-biased p-n diode
D.	reverse-biased p-n diode
Answer» D. reverse-biased p-n diode

Discussion

14.	A reverse voltage of 10 V is applied across a silicon diode. The voltage across the depletion region is approximately
A.	0 V
B.	0.7 V
C.	10 V
D.	0.2 V
Answer» D. 0.2 V

Discussion

15.	Directions: The following items consist of two statements, one labeled as “Assertion(A)” and the other labeled as “Reason(R)”. You are to examine the two statements carefully and decide if the Assertion(A) and the Reason(R) are individually true and if so whether the reason is a correct explanation of the assertion. Select your answer to these items using the codes given below and mark your answer accordingly.Assertion (A): In a p-n junction the electron crossing the junction from right to left constitutes a current in the same direction as hole crossing the junction from left to right.Reason (R): In a p-n junction the low value of depletion region capacitance can be obtained with reverse biasing.
A.	Both (A) and (R) are true and (R) is the correct explanation of (A).
B.	Both (A) and (R) are true, but (R) is not the correct explanation of (A).
C.	(A) is true, but (R) is false.
D.	(A) is false, but (R) is true.
Answer» C. (A) is true, but (R) is false.

Discussion

16.	A 24 V, 600 mW Zener diode is to be used for providing a 24 V stabilized supply to a variable load. If the input voltage is 32 V, the value of the series resistance required is:
A.	1280 Ω
B.	426 Ω
C.	960 Ω
D.	320 Ω
Answer» E.

Discussion

17.	A diode for which you can change the reverse bias and thus vary the capacitance is called
A.	Tunnel diode
B.	Varactor diode
C.	Zener diode
D.	Switching diode
Answer» C. Zener diode

Discussion

18.	A voltage regulator is used in:
A.	Sewing Machines
B.	Mobile phones
C.	Providing constant power supply to computers
D.	Refrigeration operation
Answer» C. Providing constant power supply to computers

Discussion

19.	Match List-I with List-II and select the correct answer using the codes given below the lists:List – IList – II (A) At peak point1. Low tunneling current(B) At valley point2. Zero tunneling current(C) Reverse bias region3. High diffusion current(D) Beyond valley point4. High tunneling current
A.	(A) - (3), (B) - (2), (C) - (4), (D) - (1)
B.	(A) - (1), (B) - (2), (C) - (4), (D) - (3)
C.	(A) - (3), (B) - (4), (C) - (2), (D) - (1)
D.	(A) - (1), (B) - (4), (C) - (2), (D) - (3)
Answer» B. (A) - (1), (B) - (2), (C) - (4), (D) - (3)

Discussion

20.	In a p-n diode, holes diffuse from p-region to n-region because
A.	There is higher concentration of holes in the p-region
B.	Holes are positively charged
C.	Holes are urged to move by the barrier potential
D.	Free-electron in the n-region attract the holes
Answer» B. Holes are positively charged

Discussion

21.	Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)Assertion (A): In Gunn effect, when electric field is varied from zero to a threshold value. The drift velocity decreasesReason (R): Beyond the threshold electric field, if the electric field is increased. The drift velocity is decreased and the diode exhibits negative resistance.In the light of the above statement, choose the most appropriate answer from the options given below:
A.	Both (A) and (R) are correct and (R) is the correct explanation of (A)
B.	Both (A) and (R) are correct but (R) is not the correct explanation of (A)
C.	(A) is correct but (R) is not correct
D.	(A) is not correct but (R) is correct
Answer» B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Discussion

22.	For every 10 fold increase in temperature, the reverse saturation current of a p-n junction will be increased by
A.	10 times
B.	2 times
C.	4 times
D.	remains same
Answer» C. 4 times

Discussion

23.	Avalanche breakdown occurs at a reverse bias voltage of:
A.	2 – 4 V
B.	4 – 6 V
C.	6 – 8 V
D.	8 – 10 V
Answer» E.

Discussion

24.	Consider avalanche breakdown in a silicon \(\rm p^+n\) junction. The n-region is uniformly doped with a donor density \(\rm N_D\). Assume that breakdown occurs when the magnitude of the electric field at any point in the device becomes equal to the critical field \(\rm E_{crit}\). Assume \(\rm E_{crit}\) to be independent of \(\rm N_D\). If the built-in voltage of the \(\rm p^+n\) junction is much smaller than the breakdown voltage, \(\rm V_{BR}\), the relationship between \(\rm V_{BR}\) and \(\rm N_D\) is given by
A.	\({{\rm{V}}_{{\rm{BR}}}} \times \sqrt {{{\rm{N}}_{\rm{D}}}}\) constant
B.	\({{\rm{N}}_{\rm{D}}} \times \sqrt {{{\rm{V}}_{{\rm{BR}}}}}\) constant
C.	\({{\rm{N}}_{\rm{D}}} \times {{\rm{V}}_{{\rm{BR}}}}\) constant
D.	\({{\rm{N}}_{\rm{D}}}/{{\rm{V}}_{{\rm{BR}}}}\) constant
Answer» D. \({{\rm{N}}_{\rm{D}}}/{{\rm{V}}_{{\rm{BR}}}}\) constant

Discussion

25.	How does the dynamic resistance of diode vary with temperature?
A.	Directly proportional
B.	Inversely proportional
C.	Independent
D.	Directly to the square of temperature
Answer» B. Inversely proportional

Discussion

26.	A zener diode works on the principle of
A.	tunneling of charge carriers across the junction
B.	thermionic emission
C.	diffusion of charge carriers across the junction
D.	hopping of charge carriers across the junction
Answer» B. thermionic emission

Discussion

27.	PIN diode in reverse bias condition offers
A.	zero resistance
B.	unit resistance
C.	finite resistance
D.	infinite resistance
Answer» E.

Discussion

28.	A 24 V, 600 mW Zener is to be used for providing a 24 V stabilized supply to a variable load.Assume that for proper Zener action, a minimum of 10 mA must flow through the Zener. If the input voltage is 32 V, what would be the value of R and the maximum load current?
A.	320 ohm, 10 mA
B.	400 ohm, 15 mA
C.	400 ohm, 10 mA
D.	320 ohm, 15 mA
Answer» E.

Discussion

29.	For a forward biased pn-junction diode diffusion capacitance varies
A.	Linearly with current
B.	Square of the current
C.	Inversely with current
D.	Does not vary with current
Answer» B. Square of the current

Discussion

30.	In the forward region of its characteristic, a diode appears as
A.	an OFF switch
B.	a high resistance
C.	a capacitor
D.	an ON switch
Answer» E.

Discussion

31.	In a p+n junction diode under reverse bias, the magnitude of electric field is maximum at
A.	The edge of the depletion region of the p – side
B.	The edge of the depletion region on the n – side
C.	The p+n junction
D.	The centre of the depletion region on the n – side
Answer» D. The centre of the depletion region on the n – side

Discussion

32.	An unijunction transistor (UJT) has
A.	2 p-n junctions and 2 leads
B.	1 p-n junction and 3 leads
C.	4 p-n junctions
D.	4 leads
Answer» C. 4 p-n junctions

Discussion

33.	For a silicon diode, the value of the forward bias voltage typically:
A.	must be greater than 0.3 V.
B.	must be greater than 0.7 V.
C.	depends on the width of the depletion region.
D.	depends on the concentration of the majority carriers.
Answer» C. depends on the width of the depletion region.

Discussion

34.	As compared to a full-wave rectifier using two diodes, the four diode bridge rectifier has the dominant advantage of __________.
A.	Higher current carrying capacity
B.	lower peak inverse voltage requirement
C.	lower ripple factor
D.	higher efficiency
Answer» C. lower ripple factor

Discussion

35.	Find I and V in the given circuit assuming ideal diode.
A.	2 mA, 0.6 V
B.	0 mA, 0.6 V
C.	0 mA, 5 V
D.	2 mA, -5 V
Answer» D. 2 mA, -5 V

Discussion

36.	A diode is biased at a current of 1 mA. What is the current change if VD changes by 1 mV?
A.	38.4 mA
B.	2.6 mA
C.	2.6 μA
D.	38.4 μA
Answer» E.

Discussion

37.	In a forward biased region of a pn junction diode
A.	the diode current increases exponentially with decrease in voltage
B.	the diode current decreases exponentially with increase in voltage
C.	the diode current increases exponentially with increase in voltage
D.	the diode current decreases exponentially with decrease in voltage
Answer» D. the diode current decreases exponentially with decrease in voltage

Discussion

38.	In a forward-biased pn diode, the injected hole current in the injunction is proportion to (Where Q is the total stored charge)
A.	1/Q
B.	Q
C.	Square root of Q
D.	Cube root of Q
Answer» C. Square root of Q

Discussion

39.	A one-sided abrupt pn junction diode has a depletion capacitance CD of 50 pF at a reverse bias of 0.2 V. The plot of \(\frac{1}{{C_D^2}}\) versus the applied voltage V for this diode is a straight line as shown in the figure below. The slope of the plot is ______ × 1020 F-2V-1
A.	-5.7
B.	-3.8
C.	-1.2
D.	Data insufficient
Answer» E.

Discussion

40.	A diode whose terminal characteristics are related as Id = Is(V/VT) is biased at Id = 2 mA. Its dynamic resistance is:(Given η = 2 and VT = 25 mV)
A.	25 Ω
B.	12.5 Ω
C.	50 Ω
D.	22.5 Ω
Answer» B. 12.5 Ω

Discussion

41.	In Gunn diodes, electrons are transferred from
A.	High to low mobility energy bands
B.	Low to high mobility energy bands
C.	Valley to domain formation
D.	Domain to valley formation
Answer» B. Low to high mobility energy bands

Discussion

42.	Diode is a unilateral circuit element because
A.	it can conduct current in both directions
B.	it conducts current in only one direction
C.	it is unsymmetrical in fabrication
D.	its power rating is too low
Answer» C. it is unsymmetrical in fabrication

Discussion

43.	In a zener regulator, the change in load current produces, change in ______
A.	zener voltage
B.	zener current
C.	a & b
D.	None of the above
Answer» C. a & b

Discussion

44.	In a pn junction diode under reverse bias, the magnitude of electric field is a maximum at
A.	The edge of the depletion region on the p-side
B.	The edge of the depletion region on the n-side
C.	The pn junction
D.	can’t say
Answer» D. can’t say

Discussion

45.	In a pn junction diode, \|\(\frac{{dV}}{{dT}}\)\| is equal to
A.	2.3 mV / °C
B.	3.5 mV / °C
C.	10.0 mV / °C
D.	12.5 mV / °C
Answer» B. 3.5 mV / °C

Discussion

46.	In case of varactor diode with hyper-abrupt junction the sensitivity (S) value for \(m=-\dfrac{5}{3}\) is
A.	2
B.	3
C.	1
D.	\(\dfrac{1}{2}\)
Answer» C. 1

Discussion

47.	Match List I with List II and select the correct answer using the code given below the lists: List I List IIA.Tuned circuits1.Schottky diodeB.Voltage reference2.Varactor diodeC.High-frequency switch3.PIN diodeD.Current controlled attenuator4.Zener diode
A.	A – 2, B – 4, C – 1, D - 3
B.	A – 3, B – 4, C – 1, D - 2
C.	A – 2, B – 1, C – 4, D - 3
D.	A – 3, C – 1, D – 4, D - 2
Answer» B. A – 3, B – 4, C – 1, D - 2

Discussion

48.	Match List I with List IIList I(Volt-ampere characteristics of tunnel diode)List II(Observation)(a) At peak current Ip corresponding to Vp(i) Resistance becomes and remains positive(b) If voltage increase beyond Vp(ii) Current reaches Ip (peak current) and increase(c) When voltage is just more than valley voltage(iii) \(\frac{dI}{dV}\) is negative(d) when voltage is more than peak forward voltage(iv) Slope \(\frac{dI}{dV}\) is zero Choose the correct answer from the option given below:
A.	(a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)
B.	(a) - (iv), (b) - (iii), (c) - (i), (d) - (ii)
C.	(a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)
D.	(a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)
Answer» C. (a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)

Discussion

49.	Maximum reverse bias voltage that can be applied before entering Zener region is called:
A.	Reverse voltage
B.	Peak inverse voltage
C.	Negative voltage
D.	Diode voltage
Answer» C. Negative voltage

Discussion

50.	In a PN junction depletion layer is created due to______.
A.	Diffusion of ions
B.	Diffusion of minority carriers
C.	Diffusion of Majority carriers
D.	Both 2 and 3
Answer» D. Both 2 and 3

Discussion

Explore topic-wise MCQs in Electronic Devices Circuits.

What will be the output of the following circuit? (Assume 0.7V drop across the diode)

When the diode is reverse biased with a voltage of 6V and Vbi=0.63V. Calculate the total potential.

What is the maximum electric field when Vbi=2V , VR=5V and width of the semiconductor is 7cm?

If the voltage of the potential barrier is V0. A voltage V is applied to the input, at what moment will the barrier disappear?

A TRAPATT diode has the following parameters:Doping concentration = 2 × 1015cm−3Current density = 20 KA/cm2The avalanche zone velocity of carriers is given by:

In a semiconductor diode, the cut-in voltage is the voltage:

In a p-n diode, with the increase reverse bias, the reverse current

A zener diode, when used in voltage stabilization circuits, is biased in

In an abrupt p-n junction if NA ≪ ND, then the barrier potential is:1) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}W\)2) \(\frac{{q{N_A}}}{{2{\epsilon_S}}}{W^2}\)3) \(\frac{{q{N_D}}}{{2{\epsilon_S}}}{W^2}\)4) \(\frac{{q\left( {{N_A}} \right)}}{{2{\epsilon_S}}}W\)of these statements:

In the circuit shown below if the input voltage increases, which current remains practically constant?

Diffusion capacitance is present in:

A reverse voltage of 10 V is applied across a silicon diode. The voltage across the depletion region is approximately

A 24 V, 600 mW Zener diode is to be used for providing a 24 V stabilized supply to a variable load. If the input voltage is 32 V, the value of the series resistance required is:

A diode for which you can change the reverse bias and thus vary the capacitance is called

A voltage regulator is used in:

Match List-I with List-II and select the correct answer using the codes given below the lists:List – IList – II (A) At peak point1. Low tunneling current(B) At valley point2. Zero tunneling current(C) Reverse bias region3. High diffusion current(D) Beyond valley point4. High tunneling current

In a p-n diode, holes diffuse from p-region to n-region because

For every 10 fold increase in temperature, the reverse saturation current of a p-n junction will be increased by

Avalanche breakdown occurs at a reverse bias voltage of:

How does the dynamic resistance of diode vary with temperature?

A zener diode works on the principle of

PIN diode in reverse bias condition offers

A 24 V, 600 mW Zener is to be used for providing a 24 V stabilized supply to a variable load.Assume that for proper Zener action, a minimum of 10 mA must flow through the Zener. If the input voltage is 32 V, what would be the value of R and the maximum load current?

For a forward biased pn-junction diode diffusion capacitance varies

In the forward region of its characteristic, a diode appears as

In a p+n junction diode under reverse bias, the magnitude of electric field is maximum at

An unijunction transistor (UJT) has

For a silicon diode, the value of the forward bias voltage typically:

As compared to a full-wave rectifier using two diodes, the four diode bridge rectifier has the dominant advantage of __________.

Find I and V in the given circuit assuming ideal diode.

A diode is biased at a current of 1 mA. What is the current change if VD changes by 1 mV?

In a forward biased region of a pn junction diode

In a forward-biased pn diode, the injected hole current in the injunction is proportion to (Where Q is the total stored charge)

A one-sided abrupt pn junction diode has a depletion capacitance CD of 50 pF at a reverse bias of 0.2 V. The plot of \(\frac{1}{{C_D^2}}\) versus the applied voltage V for this diode is a straight line as shown in the figure below. The slope of the plot is ______ × 1020 F-2V-1

A diode whose terminal characteristics are related as Id = Is(V/VT) is biased at Id = 2 mA. Its dynamic resistance is:(Given η = 2 and VT = 25 mV)

In Gunn diodes, electrons are transferred from

Diode is a unilateral circuit element because

In a zener regulator, the change in load current produces, change in ______

In a pn junction diode under reverse bias, the magnitude of electric field is a maximum at

In a pn junction diode, |\(\frac{{dV}}{{dT}}\)| is equal to

In case of varactor diode with hyper-abrupt junction the sensitivity (S) value for \(m=-\dfrac{5}{3}\) is

Match List I with List II and select the correct answer using the code given below the lists: List I List IIA.Tuned circuits1.Schottky diodeB.Voltage reference2.Varactor diodeC.High-frequency switch3.PIN diodeD.Current controlled attenuator4.Zener diode

Maximum reverse bias voltage that can be applied before entering Zener region is called:

In a PN junction depletion layer is created due to______.