132 + Interview Questions in Semiconductor-Diode Characteristics in Electronic Devices & Circuits Page 2 InterviewSolution

51.	By what percentage the reverse saturation current increases with 10 C rise in the temperature.(a) 25%(b) 12.5%(c) 50%(d) 7%This question was addressed to me during a job interview.My question comes from The Temperature Dependence of P-N Characteristics topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (d) 7% The explanation is: As the temperature to the P-N junction diode increases the mobility of charges increases THUS increasing the current, the reverse saturation current increases by 7% with 10C RISE in temperature and DOUBLES with every 100C rise in temperature.

Discussion

52.	In the volt ampere characteristics of the diode, the slope of the line joining the operating point to the origin at any point is equal to reciprocal of the _________(a) resistance(b) conductance(c) voltage(d) currentI had been asked this question in an interview for internship.My doubt is from Diode Resistance in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right answer is (a) resistance For explanation I would say: In the diode’s volt ampere CHARACTERISTICS, the LINE JOINING the OPERATING point and the origin, at any point of the line is equal to the conductance so, it is reciprocal of the resistance.

Discussion

53.	The cut off voltage for diode of silicon semiconductor and germanium semiconductor is ____ volts.(a) 0.5 and 0.1(b) 0.7 and 0.3(c) 1 and 0.5(d) 0.5 and 1The question was asked during a job interview.Question is taken from The Volt Ampere Characteristics topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right answer is (b) 0.7 and 0.3 Easy EXPLANATION: The CUT off VOLTAGE is the voltage only after which the SEMICONDUCTORS conduct, the cut off voltage for silicon is 0.7V in the sense the silicon diode will conduct only when voltage is more than 0.7V and 0.3 for germanium.

Discussion

54.	In a P-N junction the positive voltage at which the diode starts to conduct consequently is called.(a) Cut off voltage(b) Saturation voltage(c) Knee voltage(d) Breakdown voltageThis question was addressed to me in an interview for job.This is a very interesting question from The Volt Ampere Characteristics topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right CHOICE is (c) Knee voltage For explanation I would SAY: At a CERTAIN CRITICAL voltage, a large reverse current flows and the diode is said to be in breakdown region, at this region the diode will be forward biased and starts to conduct consequently.

Discussion

55.	Which of the following is reverse biased?(a) A)(b) B)(c) C)(d) D)I had been asked this question at a job interview.This intriguing question comes from Quantitative Theory of the P-N Diode Currents topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (c) C) The explanation is: The P-N JUNCTION diode is forward bias when the voltage APPLIED to p type is GREATER than the n type and vice versa, since the voltage applied to p type is less in C) it is the answer.

Discussion

56.	What is the thickness of ‘space charge region’ or ‘transition region’ in P-N junction diode?(a) 1 micron(b) 5 micron(c) 10 micron(d) 2.876 micronI had been asked this question in quiz.This key question is from Quantitative Theory of the P-N Diode Currents in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (a) 1 MICRON Best EXPLANATION: The region of the junction is depleted by MOBILE charges, hence it is called SPACE charge region or depletion region or transition region which is 10^-4 cm = 10^-6 m= 1 micron.

Discussion

57.	What is the total current in a diode when x=0?(a) I = Ipn (0) – Inp (0)(b) I = Ipn (0) + Inp (0)(c) I = -Ipn (0) – Inp (0)(d) I = -Ipn (0) + Inp (0)The question was posed to me during a job interview.I would like to ask this question from The Current Components in a P-N junction diode in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT CHOICE is (b) I = Ipn (0) + Inp (0) The BEST I can explain: At junction, the TOTAL CURRENT is equal to the minority hole current plus the minority electron current.

Discussion

58.	In piecewise linear characteristics what will be the RF value if the slope is 0.5?(a) 25 m ohms(b) 50 m ohms(c) 2 ohms(d) 10 ohmsThis question was posed to me during an interview.This question is from Diode Resistance in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (c) 2 ohms For explanation: In PIECEWISE LINEAR characteristics the forward RESISTANCE will be equal to RECIPROCAL of the slope so, RF = 1/slope, RF = 1/0.5 which is equal to 2 ohms.

Discussion

59.	Time taken for a diode to reach 90% of its final value when switched from steady state is______(a) 2.3time constant(b) 2.2time constant(c) 1.5*time constant(d) equals the time constantThis question was addressed to me in an interview.This intriguing question originated from PN Diode Switching Times topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT choice is (B) 2.2*time constant Best EXPLANATION: Time constant = RC. To REACH 90% of the final value, time taken is 2.2 of RC. Time constant is the time required to discharge the capacitor, through the resistor, by 36.8%.

Discussion

60.	Calculate the value of Dp when µp=400cm/s and VT=25mV.(a) 1(b) 0.01(c) 0.1(d) 10This question was addressed to me in an online quiz.This key question is from Band Structure of an Open-Circuited p-n junction topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct CHOICE is (c) 0.1 The explanation is: DP= µpVT =40010^-22510^-3 =0.1.

Discussion

61.	Calculate the value of Eowhen pno=10^4cm^-3 and ppo=10^16cm^-3 at T=300K.(a) 1meV(b) 0.7meV(c) 0.7eV(d) 0.1meVI had been asked this question in an online quiz.The origin of the question is Band Structure of an Open-Circuited p-n junction topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT OPTION is (C) 0.7eV Explanation: Eo=kTln(ppo/pno) SUBSTITUTING the VALUES, we get Eo=0.7eV.

Discussion

62.	It is possible to measure the voltage across the potential barrier through a voltmeter?(a) True(b) FalseI had been asked this question in an international level competition.The doubt is from The P-N Junction as a Diode topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct option is (B) False Easy explanation: The contacts of the VOLTMETER have some resistance which will not ACCURATELY measure the voltage across the potential barrier. Thus, it is not POSSIBLE to measure the voltage across the potential barrier.

Discussion

63.	What is the value of 1 micron?(a) 10^-6cm(b) 10^-5cm(c) 10^-4cm(d) 10^-3cmI have been asked this question in an international level competition.Query is from Qualitative Theory of the p-n junction topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (C) 10^-4cm The EXPLANATION: 1 micron=10^-4cm=10^-6cm.

Discussion

64.	Diode acts as a short circuit when switched from forward to reverse bias for some time due to______(a) Accumulation of minority charge carriers when it’s in forward bias(b) Accumulation of majority charge carrierswhen it’s in forward bias(c) Accumulation of minority charge carriers when it’s in reverse bias(d) Accumulation of majority charge carrier when it’s in reverse biasThis question was addressed to me during an online exam.The origin of the question is PN Diode Switching Times in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT ANSWER is (a) Accumulation of MINORITY charge CARRIERS when it’s in forward bias Best explanation: When a diode is switched suddenly, it persists the conducting property for a short time in its reverse bias ALSO. This leads to excess minority charge carrier settlement at potential barrier. Hence acts as a short circuit.

Discussion

65.	The built in capacitance V0 for a step graded PN junction is 0.75V. Junction capacitance Cj at reverse bias when VR=1.25V is 5pF. The value of Cj when VR=7.25V is?(a) 0.1pF(b) 1.7pF(c) 1pF(d) 2.5PfThis question was addressed to me in my homework.I'd like to ask this question from Diode Capacitances in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct OPTION is (d) 2.5Pf To EXPLAIN: We KNOW, Cj1/ Cj2=[(V0+VR2)/(V0+VR2)]^1/2 So, Cj2=Cj1/ {(0.75+7.25)/(0.75+1.25)}^1/2we GET Cj2=Cj1 /2 =5/2=2.5Pf.

Discussion

66.	In the diode volt ampere characteristics what will be the resistance if a slope is drawn between the voltages 50 to 100 and corresponding current 5 to 10?(a) 5 ohms(b) 10 ohms(c) 50 ohms(d) 100 ohmsThe question was posed to me by my school teacher while I was bunking the class.My question is taken from Diode Resistance topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT CHOICE is (b) 10 ohms The explanation is: We know that, in volt ampere characteristics the resistance is EQUAL to the reciprocal of the line joining the origin and operating point, R = dV/DI, by substituting the VALUE of dV and dI we get R= 10ohms.

Discussion

67.	If what of the following is doped into a semiconductor say germanium a P-N junction is formed.(a) Electrons and Protons(b) Protons and Neutrons(c) Neutrons and Electrons(d) Gallium and PhosphorusI have been asked this question by my college director while I was bunking the class.My query is from Quantitative Theory of the P-N Diode Currents topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT CHOICE is (d) Gallium and Phosphorus The best EXPLANATION: A P-N junction is formed only when a donor impurities and ACCEPTOR impurities are added to either side of a SEMICONDUCTOR like silicon and germanium.

Discussion

68.	In P-N junction V-I characteristics during forward biased, at what region the current increase is very low.(a) Saturation(b) Depletion(c) Cut off(d) BreakdownI had been asked this question in an interview.This is a very interesting question from The Volt Ampere Characteristics topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT option is (b) Depletion Easy explanation: In the V-I characteristics the change in the CURRENT with respect to VOLTAGE is very less in depletion region due to the large resistance in the circuit as the resistance deceases by a certain VALUE the current increases exponentially with voltage.

Discussion

69.	Rate of change of concentration per unit length in a semiconductor is called as.(a) Concentration change(b) Concentration mixture(c) Concentration gradient(d) Concentration variantI have been asked this question during an interview.I'm obligated to ask this question of Quantitative Theory of the P-N Diode Currents topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT option is (c) Concentration GRADIENT The best explanation: In a semiconductor the holes as well as ELECTRONS which are the CHARGE carriers is not equally concentrated on all REGIONS of the semiconductor the change in their rate is referred as concentration gradient.

Discussion

70.	When the diode is reverse biased with a voltage of 6V andVbi=0.63V. Calculate the total potential.(a) 6V(b) 6.63V(c) 5.27V(d) 0.63VI got this question during an interview for a job.Question is from The P-N Junction as a Diode topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» RIGHT ANSWER is (B) 6.63V Easiest EXPLANATION: Vt=Vbi+VR =0.63+6 =6V.

Discussion

71.	Which of the following statements is correct under forward biased p-n diode?(a) current enters n side as hole current and leaves p side as electron current(b) current enters n side as electron current and leaves p side as hole current(c) current enters p side as hole current and leaves n side as electron current(d) current enters p side as hole current and leaves p side as electron currentThis question was addressed to me in an interview for internship.This key question is from The Current Components in a P-N junction diode in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» RIGHT choice is (c) current enters p side as HOLE current and leaves N side as electron current The best EXPLANATION: When the current FLOWS in a p-n diode, the current enters p side as hole current and leaves n side as electron current.

Discussion

72.	Which of the following doesn’t defines for the junction which is depleted of mobile charges?(a) Depletion region(b) Uncovered region(c) Space charge region(d) Transition regionI have been asked this question during a job interview.Asked question is from Qualitative Theory of the p-n junction in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Correct answer is (b) Uncovered REGION Best explanation: The junction which is depleted of MOBILE charges is known as depletion region or SPACE charge region and TRANSITION region.

Discussion

73.	A diode will behave as an open circuit if the voltage in the circuit is less than __________(a) cut off voltage(b) saturation voltage(c) leakage voltage(d) threshold voltageThis question was posed to me in semester exam.I want to ask this question from Diode Resistance in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct option is (d) threshold voltage To explain: The diode MADE up of semiconductor has a certain threshold voltage only after which it behave as closed circuit in the sense it PERFORMS some OPERATION if the threshold voltage is GREATER than the voltage in circuit.

Discussion

74.	What will be the reverse saturation current in the junction when the voltage across the junction is 0?(a) 0.3A(b) 0.7A(c) 0A(d) 1.24AThis question was addressed to me by my school teacher while I was bunking the class.The doubt is from The Temperature Dependence of P-N Characteristics in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (c) 0A The best I can EXPLAIN: When the voltage across the junction is zero in the sense there will be potential difference between the JUNCTIONS HENCE there will be no movement of electrons and HOLES, hence the CURRENT will be 0.

Discussion

75.	In a p-n junction, the valence band edge of the p material is greater than which of the following band?(a) Conduction band edge of n material(b) Valence band edge of n material(c) Conduction band edge of p material(d) Fermi level of p materialI had been asked this question during an online interview.The above asked question is from Band Structure of an Open-Circuited p-n junction in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (B) Valence band EDGE of n MATERIAL Easy explanation: When the p-n junction is formed, the ENERGY levels of the p- material go higher than the n material. That’s why the valence band of the p material will be greater than that of the n material.

Discussion

76.	The conduction band edge in the p material is not at the same level to that of conduction band edge in the n material. Is it true or false?(a) True(b) FalseThis question was posed to me by my college director while I was bunking the class.I would like to ask this question from Band Structure of an Open-Circuited p-n junction in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (a) True Explanation: In a p-n JUNCTION diode, the energy LEVELS of the p MATERIAL and n material will not be at same level. They will be different. So, the conduction band edge as well as the valence band edge of the p material will not be same to that of the n material.

Discussion

77.	Transition capacitance is also called as _______(a) diffusion capacitance(b) depletion capacitance(c) conductance capacitance(d) resistive capacitanceI have been asked this question during an online interview.This intriguing question originated from Diode Capacitances topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT answer is (b) DEPLETION capacitance Easiest explanation: TRANSITION capacitance occurs in reverse BIAS. We obtain a depletion layer in that case. Hence it’s also called as depletion capacitance. The diffusion capacitance occurs in FORWARD bias.

Discussion

78.	For an abrupt PN junction diode, small signal capacitance is 1nF/cm^2 at zero bias condition.If the built in voltage, Vbi is 1V, the capacitance at reverse bias of 99V is?(a) 0.1nF/cm^2(b) 1nF/cm^2(c) 1.5nF/cm^2(d) 2nF/cm^2This question was addressed to me in examination.I need to ask this question from Diode Capacitances in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (a) 0.1nF/cm^2 Easiest EXPLANATION: CJO is the capacitance at zero bias, that is VR=0V, Cjo=CJ for VR=0V. We know, Cj = Cjo/(1+(VR/Vbi))m , m=1/2 for ABRUPT. So, puttingCj=0.1nF/cm^2 where, VR=99V andVbi=1V we GET, Cjo= 0.1(1+99)^1/2 = 0.1nF/cm^2.

Discussion

79.	What will be the approximate value of thermal voltage of diode?(a) 25mV at 300K(b) 30mV at 180K(c) 25mV at 180K(d) 30mV at 300KI had been asked this question in semester exam.My doubt stems from Diode Resistance in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Correct option is (a) 25mV at 300K The EXPLANATION: We know that the THERMAL voltage of diode is approximately equal to ROOM TEMPERATURE which is 300K then for all practical purpose the thermal voltage of diode is TAKEN as 25mV so it will be 25mV at 300K.

Discussion

80.	If the drift current is 100mA and diffusion current is 1A what is the total current in the semiconductor diode.(a) 1.01 A(b) 1.1 A(c) 900m A(d) 10 AThis question was addressed to me in a national level competition.My query is from Quantitative Theory of the P-N Diode Currents in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct option is (b) 1.1 A To explain I would SAY: We know that the total current in a SEMICONDUCTOR is equal to sum of both drift current and DIFFUSION current. Total current = 1A + 100mA =1.1A.

Discussion

81.	At room temperature (VT = 26) what will be the approximate value of r when n=1 and I=100mA?(a) 26 ohms(b) 2.6 ohms(c) 260 ohms(d) 2600 ohmsThe question was asked by my college director while I was bunking the class.This intriguing question originated from Diode Resistance in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Correct OPTION is (C) 260 ohms Explanation: We know that R= (nVT) /I, by substituting the VALUE of n, VT, I we GET R= 260 ohms, (126)/100*10^-3 = 260 ohms.

Discussion

82.	Convert 10 micron to meters.(a) 10^-5m(b) 10^7m(c) 10^-6m(d) 10^-4mI have been asked this question at a job interview.This key question is from Qualitative Theory of the p-n junction topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right option is (a) 10^-5m Easy EXPLANATION: Since, 1 MICRON=10^-6m 10 micron =10^-5m.

Discussion

83.	What does Inp represent?(a) Hole current in n region(b) Hole current in p region(c) Electron current in n region(d) Electron current in p regionThis question was posed to me in a national level competition.This key question is from The Current Components in a P-N junction diode in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» RIGHT option is (d) ELECTRON current in p REGION To elaborate: Inp CONSTITUTES of the electron current in the p region. It is the minority electron CARRIER in the p region.

Discussion

84.	Calculate Vo when ppo=10^16cm^-3, pno=10^4cm^-3 and Vt=25mV.(a) 69V(b) 6.9V(c) 0.69V(d) 0.069VThis question was posed to me in class test.I need to ask this question from Band Structure of an Open-Circuited p-n junction topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT OPTION is (c) 0.69V To EXPLAIN: Vo=VTln⁡(ppo/pno ) =2510^-3LN(10^16/10^4) =0.69V.

Discussion

85.	What is the value of kT at room temperature?(a) 0.0256eV(b) 0.25eV(c) 25eV(d) 0.0025eVI had been asked this question in an international level competition.I want to ask this question from Band Structure of an Open-Circuited p-n junction in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» RIGHT CHOICE is (a) 0.0256eV Explanation: kT=1.3810^-23300K =4.1410^-21/ (1.610^-19) =0.0256eV.

Discussion

86.	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) 0VI had been asked this question in exam.Asked question is from The P-N Junction as a Diode topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (C) 11.3V Easiest EXPLANATION: V=12-0.7 =11.3V.

Discussion

87.	A PN junction diode with 100Ω resistor is forward biased such that 100A current flows. If voltage across this combination is instantaneously reversed to 10V at t=0, the reverse current that flows through diode at t=0 is?(a) 10mA(b) 100mA(c) -100mA(d) -10mAThis question was addressed to me during a job interview.I would like to ask this question from PN Diode Switching Times topic in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (B) 100mA Easy EXPLANATION: At t=0, V=-10V. During storage TIME, current still flows. We KNOW that, current I=V/R=10/100Ω=100mA from N to P region.

Discussion

88.	Which of these following is not a characteristic of an ideal diode?(a) Perfect conductor when forward bias(b) Zero voltage across it when forward bias(c) Perfect insulator when reverse bias(d) Zero current through it when forward biasI got this question during an internship interview.The above asked question is from Diode Resistance in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT option is (d) Zero current through it when forward BIAS To explain: The diode acts as an IDEAL diode when it is a perfect CONDUCTOR and has zero VOLTAGE across it during forward bias, a perfect insulator and zero current through it during reverse bias.

Discussion

89.	What is the hole current in the p region of the diode?(a) Ipp (x)=I-Inp (x)(b) Ipp (x)=I+Inp (x)(c) Ipp (x)=-I-Inp (x)(d) Ipp (x)=-I+Inp (x)I had been asked this question in a job interview.Question is from The Current Components in a P-N junction diode in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (a) Ipp (x)=I-Inp (x) Explanation: The HOLE CURRENT in the p region is equal to the TOTAL current minus the minority ELECTRONS in the p region.

Discussion

90.	Calculate the total current when Ipn (0)=1mA and Inp (0)=2mA.(a) 1mA(b) -1mA(c) 0(d) 3mAThis question was addressed to me in an online quiz.Query is from The Current Components in a P-N junction diode in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT CHOICE is (d) 3mA The BEST EXPLANATION: I=Ipn (0)+Inp (0) =1mA+2mA =3mA.

Discussion

91.	If the positive terminal of the battery is connected to the anode of the diode, then it is known as(a) Forward biased(b) Reverse biased(c) Equilibrium(d) Schottky barrierThis question was posed to me by my school principal while I was bunking the class.This interesting question is from The P-N Junction as a Diode topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct CHOICE is (a) Forward biased The best I can EXPLAIN: When a positive terminal is connected to the anode, the DIODE is forward biased which LETS the flow of the current in the circuit.

Discussion

92.	Which of the following options doesn’t defined for the necessity for the existence of the potential barrier?(a) Contact(b) Potential(c) Diffusion(d) Fermi diracThis question was addressed to me during an interview.Enquiry is from Qualitative Theory of the p-n junction in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The CORRECT option is (d) Fermi dirac Best EXPLANATION: The potential BARRIER is formed at the junction of the SEMICONDUCTOR. It’s NECESSITY of the potential barrier is known as the contact, potential or diffusion.

Discussion

93.	In a P-N junction diode during forward bias if the current increases more than the value that is rated will destroy the diode.(a) True(b) FalseI got this question in a job interview.Question is taken from The Volt Ampere Characteristics topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct option is (a) True Easiest explanation: If the current in the P-N junction DIODE during forward BIAS increases beyond the VALUE rated on it will destroy the diode because voltage is directly proportional to current so EXTREME voltage will burn the diode down.

Discussion

94.	The delay in switching between the ON and OFF states is due to _________(a) The time required to change amount of excess minority carriers stored in quasi-neutral regions(b) The time required to change amount of excess majority carriers stored in quasi-neutral regions(c) The conduction between storage time and recovery time(d) The exponential increase in carriers in N regionI had been asked this question in a job interview.This intriguing question comes from PN Diode Switching Times topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right answer is (a) The time required to change amount of excess minority carriers stored in quasi-neutral regions Easiest EXPLANATION: When switched instantaneously it STAYS in a quasi state i.e.., TEMPORARY state which stores CHARGES. The delay is produced due to this charge settlement. The diode needs to discharge these excess carriers in order to return the non conduction stage.

Discussion

95.	The current is constant throughout the device. Is it true or false?(a) True(b) FalseThe question was posed to me in examination.The question is from The Current Components in a P-N junction diode in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right option is (a) True For explanation: The CURRENT in the DEVICE is constant but the PROPORTION due to the electrons and holes VARIES with distance.

Discussion

96.	The number of injected minority carriers falls off linearly with the increase in the distance from the junction. Is it true or false?(a) True(b) FalseThe question was asked in an internship interview.My query is from The Current Components in a P-N junction diode in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» RIGHT answer is (b) False To explain I would say: The number of minority carriers FALL off exponentially rather than LINEARLY with the increase in the DISTANCE from the junction.

Discussion

97.	Is Vo depends only on the equilibrium concentrations. Is it true or false?(a) True(b) FalseI had been asked this question in an online interview.The question is from Band Structure of an Open-Circuited p-n junction topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Right choice is (a) True To EXPLAIN I would SAY: Vo is the CONTACT potential of the junction when the junction is in EQUILIBRIUM. If, the junction is not in the equilibrium, Vo can’t be CALCULATED.

Discussion

98.	During reverse bias, a small current develops known as(a) Forward current(b) Reverse current(c) Reverse saturation current(d) Active currentI had been asked this question in class test.This is a very interesting question from The P-N Junction as a Diode in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (C) Reverse SATURATION current To explain: When the DIODE is reverse biased, a small current flows between the p-n junction which is of the order of the Pico AMPERE. This current is KNOWN as reverse saturation current.

Discussion

99.	What will be the decrease of barrier voltage with the rise in 10C in temperature?(a) 10V(b) 1mV(c) 10mV(d) 2mVThe question was asked in homework.This key question is from The Temperature Dependence of P-N Characteristics topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» Correct ANSWER is (d) 2mV Best explanation: As the temperature to the P-N junction DIODE INCREASES the voltage across the junction decreases and the current increases with every DEGREE rise in temperature the barrier voltage increases by 2mV.

Discussion

100.	The magnitude of the electric charge (e) is given by ____________(a) -1.610^-19 C(b) 1.610-^19 C(c) 9.1110-^31 C(d) 1.63710^-37 CI have been asked this question by my school teacher while I was bunking the class.My question is based upon The Temperature Dependence of P-N Characteristics in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits
Answer» CORRECT CHOICE is (a) -1.610^-19 C For explanation I would say: The charge of the electron is the MAGNITUDE of electric force that an electron EXERTS on other particles which is equal to -1.610^-19 C, the negative sign indicates the direction of force.

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following is reverse biased?(a) A)(b) B)(c) C)(d) D)I had been asked this question at a job interview.This intriguing question comes from Quantitative Theory of the P-N Diode Currents topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits

In piecewise linear characteristics what will be the RF value if the slope is 0.5?(a) 25 m ohms(b) 50 m ohms(c) 2 ohms(d) 10 ohmsThis question was posed to me during an interview.This question is from Diode Resistance in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits

Calculate the value of Dp when µp=400cm/s and VT=25mV.(a) 1(b) 0.01(c) 0.1(d) 10This question was addressed to me in an online quiz.This key question is from Band Structure of an Open-Circuited p-n junction topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits

What is the value of 1 micron?(a) 10^-6cm(b) 10^-5cm(c) 10^-4cm(d) 10^-3cmI have been asked this question in an international level competition.Query is from Qualitative Theory of the p-n junction topic in section Semiconductor-Diode Characteristics of Electronic Devices & Circuits

What will be the approximate value of thermal voltage of diode?(a) 25mV at 300K(b) 30mV at 180K(c) 25mV at 180K(d) 30mV at 300KI had been asked this question in semester exam.My doubt stems from Diode Resistance in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits

Convert 10 micron to meters.(a) 10^-5m(b) 10^7m(c) 10^-6m(d) 10^-4mI have been asked this question at a job interview.This key question is from Qualitative Theory of the p-n junction topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits

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) 0VI had been asked this question in exam.Asked question is from The P-N Junction as a Diode topic in chapter Semiconductor-Diode Characteristics of Electronic Devices & Circuits

Calculate the total current when Ipn (0)=1mA and Inp (0)=2mA.(a) 1mA(b) -1mA(c) 0(d) 3mAThis question was addressed to me in an online quiz.Query is from The Current Components in a P-N junction diode in division Semiconductor-Diode Characteristics of Electronic Devices & Circuits

The current is constant throughout the device. Is it true or false?(a) True(b) FalseThe question was posed to me in examination.The question is from The Current Components in a P-N junction diode in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits