92 + Interview Questions in Transistor Characteristics in Electronic Devices & Circuits Page 1 InterviewSolution

1.	The point on the DC load line which is represented by ‘Q’ is called _________(a) cut off point(b) cut in point(c) breakdown point(d) operating pointI got this question during an online exam.This key question is from The Common Collector Configuration in section Transistor Characteristics of Electronic Devices & Circuits
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2.	The CC configuration has an input resistance_________(a) 500kΩ(b) 750kΩ(c) 600kΩ(d) 400kΩI got this question in an internship interview.I would like to ask this question from The Common Collector Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits
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Discussion

3.	The negative sign in the formula of amplification factor indicates_________(a) that IE flows into transistor while IC flows out it(b) that IC flows into transistor while IE flows out it(c) that IB flows into transistor while IC flows out it(d) that IC flows into transistor while IB flows out itThis question was addressed to me during an interview for a job.Query is from The Common Base Configuration topic in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» The CORRECT choice is (a) that IE flows into transistor while IC flows out it The best I can explain: When no signal is APPLIED, the ratio of collector current to emitter current is called DC alpha, αdc of a transistor. αdc=-IC/IE. It is the measure of the quality of a transistor. Higher is the value of α, better is the transistor in the sense that collector current approaches the emitter current.

Discussion

4.	In ICEO, wt does the subscript ‘CEO’ mean?(a) collector to base emitter open(b) emitter to base collector open(c) collector to emitter base open(d) emitter to collector base openI have been asked this question in class test.This interesting question is from The Common Emitter Configuration in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct option is (c) collector to emitter base open Easiest EXPLANATION: The subscript ‘CEO’ means that it is collector to emitter base open. It is CALLED as the leakage current. It occurs in a REVERSE BIAS in PNP transistor. The total current can be calculated by IC=βIB+IC.

Discussion

5.	The collector current will not reach the steady state value instantaneously because of_________(a) stray capacitances(b) resistances(c) input blocking capacitances(d) coupling capacitanceI have been asked this question in an interview for job.I'd like to ask this question from Transistor Switching Times topic in division Transistor Characteristics of Electronic Devices & Circuits
Answer» The CORRECT answer is (a) stray capacitances The explanation is: When a pulse is given, the collector CURRENT will not reach the STEADY STATE value instantaneously because of stray capacitances. The charging and DISCHARGING of capacitance makes the current to reach a steady state value after a given time constant.

Discussion

6.	The input characteristics of a CB transistor resembles_________(a) Forward biased diode(b) Illuminated photo diode(c) LED(d) Zener diodeThis question was posed to me in a national level competition.My doubt is from The CB Characteristics topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct option is (B) Illuminated PHOTO diode Explanation: The INPUT CHARACTERISTICS resemble the illuminated photo diode and the output characteristics resemble the FORWARD biased diode. This transistor has low input impedance and high output impedance.

Discussion

7.	What is the output resistance of CC transistor?(a) 25 Ω(b) 50 Ω(c) 100 Ω(d) 150 ΩI have been asked this question in an internship interview.My enquiry is from The Common Collector Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (a) 25 Ω Explanation: The CC transistor has a very low value of OUTPUT resistance of 25 Ω. The voltage GAIN is always less one. It is used for driving a low impedance load from a HIGH impedance source.

Discussion

8.	The emitter current consist of_________(a) electrons passing from collector to emitter(b) holes crossing from base to collector(c) electron current Ine constituted by electrons(d) immobile charge carriersI have been asked this question by my school principal while I was bunking the class.This interesting question is from The Transistor as an Amplifier in division Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct choice is (c) electron current INE constituted by electrons Easiest EXPLANATION: The emitter current consists of two parts. It consists of hole current IPE constituted by HOLES. The other part is that it consists the electron current InE constituted by electrons.

Discussion

9.	Which of the following are true for a PNP transistor?(a) the emitter current is less than the collector current(b) the collector current is less than the emitter current(c) the electrons are majority charge carriers(d) the holes are the minority charge carriersThe question was posed to me at a job interview.Origin of the question is The Junction Transistor in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct option is (b) the collector CURRENT is less than the emitter current For explanation: The 2 – 5% of holes is lost in recombination with electrons in the base region. The majority CHARGE carriers are holes for a PNP transistor. Thus the collector current is slightly less than the emitter current.

Discussion

10.	The base emitter voltage in a cut off region is_________(a) greater than 0.7V(b) equal to 0.7V(c) less than 0.7V(d) cannot be predictedI got this question in unit test.This question is from Transistor as a Switch in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» Right answer is (c) less than 0.7V For explanation: From the CUT off CHARACTERISTICS, the base emitter voltage (VBE) in a cut off REGION is less than 0.7V. The cut off region can be considered as ‘off mode’. Here, VBE > 0.7 and IC=0. For a PNP transistor, the emitter POTENTIAL must be negative with respect to the base.

Discussion

11.	For the circuit shown, find the quiescent point.(a) (10V, 4mA)(b) (4V, 10mA)(c) (10V, 3mA)(d) (3mA, 10V)I got this question by my school principal while I was bunking the class.The above asked question is from DC Load Lines topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Right ANSWER is (c) (10V, 3MA) The explanation is: We know, IE=VEE/RE=10/5kΩ=2mA IC=α IE =IE =2mA VCB=VCC-ICRL=20-10=10V. So, QUIESCENT point is (10V, 2mA).

Discussion

12.	Which of the following cases damage the transistor?(a) when VCE is increased too far(b) when VCE is decreased too far(c) when VBE is increased too far(d) when VBE is decreased too farI had been asked this question during a job interview.This question is from The CE Characteristics topic in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» Right choice is (a) when VCE is increased too far Explanation: When VCE is increased too far, collector base junction completely breaks down and due to this avalanche breakdown, collector current increases rapidly. This is not SHOWN in the characteristic. In this CASE, the TRANSISTOR is DAMAGED.

Discussion

13.	The output resistance is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VCE/∆ICI have been asked this question during an interview.Query is from The CE Characteristics in division Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (d) ∆VCE/∆IC Easiest explanation: The RATIO of CHANGE in collector emitter VOLTAGE (∆VCE) to resulting change in collector CURRENT (∆IC) at constant base current (IB) is defined as output resistance. This is denoted by ro.

Discussion

14.	Increase in collector emitter voltage from 5V to 8V causes increase in collector current from 5mA to 5.3mA. Determine the dynamic output resistance.(a) 20kΩ(b) 10kΩ(c) 50kΩ(d) 60kΩI got this question during an internship interview.My doubt is from The Common Collector Configuration in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» RIGHT ANSWER is (B) 10kΩ Explanation: ro=∆VCE/∆IC =3/0.3m=10kΩ.

Discussion

15.	The non rectifying base contact is made from_________(a) welding a strip(b) germanium(c) indium(d) graphiteThis question was posed to me in an international level competition.I want to ask this question from Transistor Construction in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» Right CHOICE is (a) welding a STRIP The explanation: LEADS for emitter and collector are soldered to the dots making NON rectifying contacts. Further, non rectifying base contact is usually made from a welding a strip or loop of gold plated WIRE to the base plate.

Discussion

16.	Which of the following methods take impurity variation method for transistor construction?(a) alloy type diffusion(b) grown junction type(c) epitaxial type(d) mesa typeI had been asked this question in unit test.My query is from Transistor Construction topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (b) grown junction TYPE The explanation: In IMPURITY variation method, the impurity content of the SEMICONDUCTOR is altered in its type as WELL as the quantity. For example, in making NPN germanium grown junction transistor, a small type of N type impurity is added to molten germanium and the crystal growth is started.

Discussion

17.	Why is the silicon mostly chosen when compared to germanium?(a) low power consumption(b) high efficiency(c) greater working temperature(d) large ICBOI got this question in an international level competition.This interesting question is from The Transistor as an Amplifier in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (c) greater working temperature To explain I WOULD SAY: The normal working temperature of GERMANIUM is approximately 70°C .The normal working temperature of silicon is approximately 150°C. The other advantages of using a silicon material are, it has a smaller ICBO and its VARIATIONS are smaller with temperature.

Discussion

18.	What is the left hand section of a junction transistor called?(a) base(b) collector(c) emitter(d) depletion regionI have been asked this question in an interview for job.This interesting question is from The Junction Transistor topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct choice is (c) emitter To ELABORATE: The MAIN function of this section is to supply majority charge carriers to the base. Hence it is more heavily doped in comparison to other regions. This forms the LEFT HAND section of the TRANSISTOR.

Discussion

19.	The AC current gain in a common base configuration is_________(a) -∆IC/∆IE(b) ∆IC/∆IE(c) ∆IE/∆IC(d) -∆IE/∆ICThe question was asked in unit test.My question is from The Common Base Configuration in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct choice is (a) -∆IC/∆IE Best explanation: The AC current gain is denoted by αac. The ratio of CHANGE in collector current to the change in emitter current at CONSTANT collector base voltage is DEFINED as current AMPLIFICATION factor.

Discussion

20.	The input of a CB transistor is given between_________(a) collector and emitter terminals(b) base ad collector terminals(c) ground and emitter terminals(d) emitter and base terminalsI got this question during an interview.My question is from The CB Characteristics in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» Right choice is (d) emitter and base TERMINALS For explanation: The name of the CB transistor says that it’s a common BASED one. The input is given between the emitter and base terminals and the OUTPUT is TAKEN between collectorand base terminals.

Discussion

21.	The switching of power with a NPN transistor is called_________(a) sourcing current(b) sinking current(c) forward sourcing(d) reverse sinkingThe question was asked during an interview.I want to ask this question from Transistor as a Switch in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» RIGHT choice is (b) sinking current Best explanation: SOMETIMES DC current gain of a bipolar TRANSISTOR is too low to directly SWITCH the load current or voltage, so multiple SWITCHING transistors is used. The load is connected to supply and the transistor switches the power to it.

Discussion

22.	Which of the following statements is true?(a) Solid state switches are applications for an AC output(b) LED’s can be driven by transistor logics(c) Only NPN transistor can be used as a switch(d) Transistor operates as a switch only in active regionThe question was posed to me in a job interview.I'm obligated to ask this question of Transistor as a Switch in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (b) LED’s can be driven by transistor logics To explain I would say: Output devices like LED’s only REQUIRE a few milliamps at logic level DC voltages and can THEREFORE be driven directly by the output of a logic gate. HOWEVER, high power devices such as motors or LAMPS require more power than that supplied by an ordinary logic gate so transistor SWITCHES are used.

Discussion

23.	The DC equivalent circuit for an NPN common emitter circuit is.I have been asked this question during an online interview.The question is from DC Load Lines topic in division Transistor Characteristics of Electronic Devices & Circuits
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24.	The input resistance in a CB transistor is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VEB/∆IEI have been asked this question in a job interview.The query is from The CB Characteristics in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (d) ∆VEB/∆IE Easy EXPLANATION: The RATIO of change in emitter BASE voltage (∆VEB) to resulting change in emitter current (∆IE) at constant COLLECTOR base voltage (VCB) is defined as input resistance. This is denoted by ri.

Discussion

25.	The relation between α and β is given by _________(a) 1/(1-α)=1- β(b) 1/(1+α)=1+ β(c) 1/(1-α)=1+ β(d) 1/(1+α)=1- βI have been asked this question by my college professor while I was bunking the class.Question is from The Common Collector Configuration in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» RIGHT option is (c) 1/(1-α)=1+ β For explanation I WOULD say: The current amplification factor (β) is given by IC//IB. When no signal is applied, then the ratio of collector current to the base current is called current amplification factor of a TRANSISTOR. β is an AC base amplification factor. α is called as current amplification factor. The relation of IC and IB change as IC= βIB+ (1+ β) ICBO.

Discussion

26.	Which of the following points locates the quiescent point?(a) (IC, VCB)(b) (IE, VCE)(c) (IE, VCB)(d) (IC, VCE)I got this question in semester exam.Question is taken from The CE Characteristics in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» RIGHT answer is (a) (IC, VCB) The EXPLANATION is: The quiescent point is best located between the CUT off and SATURATION point. IE= VEE/RE, VCB=VCC-ICRL. It is denoted by ‘Q’.

Discussion

27.	The range of β is _________(a) 20 to 500(b) 50 to 300(c) 30 to 400(d) 10 to 20This question was addressed to me at a job interview.My query is from The Common Emitter Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (a) 20 to 500 For explanation I would say: ALMOST in all the transistors, the base current is LESS than 5% of the emitter current. Due to this fact, it is generally greater than 20. Usually it ranges from 20 to 500. Hence this configuration is frequently USED when appreciable current gain as well as VOLTAGE gain is required.

Discussion

28.	The value of αac for all practical purposes, for commercial transistors range from_________(a) 0.5-0.6(b) 0.7-0.77(c) 0.8-0.88(d) 0.9-0.99The question was asked in a national level competition.I need to ask this question from The Common Base Configuration in section Transistor Characteristics of Electronic Devices & Circuits
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29.	A germanium transistor used as an amplifier has a collector cut off current ICBO=10µA at a temperature 27°C and β=50. What is the collector current when the base current is 0.25mA?(a) 10.76mA(b) 13.01mA(c) 15.67mA(d) 11.88MaThis question was addressed to me in my homework.I'd like to ask this question from The Transistor as an Amplifier in portion Transistor Characteristics of Electronic Devices & Circuits
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Discussion

30.	What is the melting point of indium in alloy type transistors?(a) 300°C(b) 200°C(c) 155°C(d) 100°CI have been asked this question in an online quiz.My doubt is from Transistor Construction topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» CORRECT ANSWER is (c) 155°C Explanation: This is SIMILAR to soldering and PNP transistor is generally is made by this process. In this method, first of all N type germanium is obtained. The N type wafer and indium dots are placed in a furnace and HEATED to about 500°C.

Discussion

31.	The total emitter current (IE) is given by_________(a) IE = IpE * InE(b) IE = IpE – InE(c) IE = IpE / InE(d) IE = IpE + InEI have been asked this question in a job interview.My question is from The Transistor as an Amplifier topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct option is (d) IE = IPE + InE The explanation is: The total emitter current is the sum of InE and IpE. In commercial TRANSISTORS, the doping of emitter region is MADE much heavier than BASE. Hence current by majority CHARGE carriers InE is negligible when compared to current by minority charge carriers IpE.

Discussion

32.	In the saturated region, the transistor acts like a_________(a) poor transistor(b) amplifier(c) open switch(d) closed switchThe question was asked in homework.This intriguing question originated from The Junction Transistor topic in division Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct option is (d) CLOSED SWITCH Best explanation: In saturated mode, both emitter and collector are forward biased. The NEGATIVE of the battery is connected to emitter and similarly the positive terminals of BATTERIES are connected to the base. The transistor now acts like a closed switch.

Discussion

33.	The technique used to quickly switch off a transistor is by_________(a) reverse biasing its emitter to collector junction(b) reverse biasing its base to collector junction(c) reverse biasing its base to emitterjunction(d) reverse biasing any junctionThis question was addressed to me during an online interview.The above asked question is from Transistor Switching Times topic in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» RIGHT CHOICE is (c) reverse biasing its base to emitterjunction For explanation: The technique used to QUICKLY SWITCH off a transistor is by reverse biasing its base to collector junction. It is demonstrated in a high voltage switching circuit. The ADVANTAGE of this circuit is that it is not necessary to have high voltage control signal.

Discussion

34.	Which of the following helps in reducing the switching time of a transistor?(a) a resistor connected from base to ground(b) a resistor connected from emitter to ground(c) a capacitor connected from base to ground(d) a capacitor connected from emitter to groundThe question was asked in an online interview.My query is from Transistor Switching Times in division Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (a) a RESISTOR connected from base to ground To explain: Connecting a resistor connected from base of a transistor to ground/negative voltage HELPS in REDUCING the SWITCHING the switching TIME of the transistor. When transistor saturate, there is stored charge in the base that must be removed before it turns off.

Discussion

35.	The base emitter voltage in a saturation region is_________(a) greater than 0.7V(b) equal to 0.7V(c) less than 0.7V(d) cannot be predictedI have been asked this question in an interview for internship.I need to ask this question from Transistor as a Switch in division Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (d) cannot be predicted Explanation: From the saturation mode characteristics, the transistor acts as a single POLE single throw SOLID state switch. A zero COLLECTOR current flows. With a positive signal APPLIED to the base of transistor it TURNS on like a closed switch.

Discussion

36.	For the circuit shown, find the quiescent point.(a) (10V, 4mA)(b) (4V, 10mA)(c) (10V, 3mA)(d) (3mA, 10V)I had been asked this question in final exam.The doubt is from DC Load Lines topic in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct CHOICE is (c) (10V, 3mA) For explanation I would say: We KNOW, IE=VEE/RE=30/10kΩ=3mA IC=α IE =IE =3mA VCB=VCC-ICRL=25-15=10V. So, quiescent point is (10V, 3mA).

Discussion

37.	A change in 300mV in base emitter voltage causes a change of 100µA in the base current. Determine the dynamic input resistance.(a) 20kΩ(b) 10kΩ(c) 30kΩ(d) 60kΩI had been asked this question during an interview for a job.I need to ask this question from The Common Collector Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (C) 30kΩ Explanation: ro=∆VBE/∆IB =300m/100µ=30kΩ.

Discussion

38.	If the emitter-base junction is forward biased and the collector-base junction is reverse biased, what will be the region of operation for a transistor?(a) cut off region(b) saturated region(c) inverted region(d) active regionThe question was asked at a job interview.Question is from The Junction Transistor topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Right OPTION is (d) active region The explanation is: When the emitter-base junction is forward biased and the collector-base junction is reverse biased, the TRANSISTOR is used for amplification. A BATTERY is CONNECTED to collector base circuit. The positive TERMINAL is connected to the collector while the negative is connected to the base.

Discussion

39.	When does the transistor act like an open switch?(a) cut off region(b) inverted region(c) saturated region(d) active regionThe question was asked during an interview.The query is from The Junction Transistor topic in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» CORRECT option is (a) cut off region Easy explanation: In cut off region, both the junctions are reverse BIASED. The transistor has practically zero current because the emitter does not EMIT CHARGE carriers to the base. So, the transistor acts as OPEN switch.

Discussion

40.	The base emitter voltage in a cut off region is _________(a) greater than 0.7V(b) equal to 0.7V(c) less than 0.7V(d) cannot be predictedI got this question in an interview for job.I need to ask this question from Transistor Switching Times in chapter Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct choice is (C) LESS than 0.7V Easiest explanation: From the cut off characteristics, the base EMITTER voltage (VBE) in a cut off region is less than 0.7V. The cut off region can be considered as ‘off MODE’. Here, VBE < 0.7 and IC=0. For a PNP transistor, the emitter potential MUST be negative with respect to the base.

Discussion

41.	The current which is helpful for LED to turn on is_________(a) emitter current(b) base current(c) collector current(d) depends on biasThe question was posed to me during an interview for a job.Query is from Transistor as a Switch topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct option is (c) collector current The EXPLANATION is: Depending on the type of load, a collector current is induced that would turn on the MOTOR or LED. The transistor in the circuit is SWITCHED between cut off and saturation. The load, for example, can be a motor or a LIGHT emitting diode or any other electrical device.

Discussion

42.	In which region a transistor acts as a closed switch?(a) cut off region(b) inverted region(c) active region(d) saturated regionThe question was asked in a national level competition.Question is taken from Transistor as a Switch topic in division Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (d) saturated region Best EXPLANATION: In this mode, both the junctions are FORWARD biased. The NEGATIVE terminal of the BATTERY is connected to the emitter. The collector current becomes independent of base current. In this mode the transistor ACTS as a closed switch.

Discussion

43.	A change in 700mV in base emitter voltage causes a change of 200µA in the base current. Determine the dynamic input resistance.(a) 2kΩ(b) 10kΩ(c) 3kΩ(d) 3.5kΩThe question was asked in an interview for internship.This intriguing question comes from The CE Characteristics topic in division Transistor Characteristics of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (C) 3kΩ To ELABORATE: ro=∆VBE/∆IB =700m/200µ=3.5kΩ.

Discussion

44.	The input resistance is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VBE/∆IEI got this question during an online interview.I would like to ask this question from The CE Characteristics topic in division Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct answer is (B) ∆VBE/∆IB The explanation is: The ratio of change in base emitter VOLTAGE (∆VBE) to resulting change in base current (∆IB) at constant collector emitter voltage (VCE) is defined as input RESISTANCE. This is DENOTED by RI.

Discussion

45.	The relation between α and β is_________(a) β = α/ (1-α)(b) α = β/(1+β)(c) β = α/ (1+α)(d) α = β/(1- β)The question was asked in a job interview.The query is from The Common Emitter Configuration topic in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct option is (b) α = β/(1+β) Easiest explanation: β is an ac BASE amplification FACTOR. α is CALLED as current amplification factor. The RELATION of IC and IB change as IC= βIB+ (1+ β) ICBO.

Discussion

46.	The electrical properties of a transistor in alloy type construction is determined by_________(a) space between the junctions in the wafer(b) proportions of N and P type impurities(c) the pulling rate of crystal(d) uniformity of the crystal latticeThis question was posed to me in an internship interview.My enquiry is from Transistor Construction in section Transistor Characteristics of Electronic Devices & Circuits
Answer» CORRECT answer is (a) space between the junctions in the wafer To elaborate: Large area collector junction helps in collecting most of the holes emitted from the emitter ENSURING that the collector current almost EQUALS the emitter current. The spacing between TWO junctions inside germanium wafer is very small and determines the electrical properties.

Discussion

47.	The larger dot of the indium is used as_________(a) base(b) emitter(c) control pin(d) collectorThis question was addressed to me in my homework.This interesting question is from Transistor Construction in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (d) collector Best explanation: The wafer is placed in a GRAPHITE JIG with a dot of prepared indium. One dot of an indium is 3 times larger than the other. Finally the larger dot is used as collector. The smaller dot is used as EMITTER.

Discussion

48.	In a PNP germanium transistor, the cut in voltage is about_________(a) -0.1V(b) -0.01V(c) -0.05V(d) -0.07VThis question was addressed to me in exam.Asked question is from The Transistor as an Amplifier topic in section Transistor Characteristics of Electronic Devices & Circuits
Answer» The correct answer is (a) -0.1V Easiest EXPLANATION: The cut in VOLTAGE of germanium is lower than that of SILICON. If both germanium and silicon are in parallel, GE starts conducting EARLIER and stops silicon from conducting.

Discussion

49.	The amplification factor for a transistor is given by_________(a) A=αRL/re(b) A=αRLre(c) A=re/ αRL(d) A=RL/reαThis question was posed to me in an interview for job.The question is from The Transistor as an Amplifier topic in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» Right option is (a) A=αRL/re The explanation is: One of the most important application of a transistor is an AMPLIFIER. A small change in signal voltage PRODUCES an appreciable change in EMITTER current because the INPUT circuit has low resistance (α=∆IC/IE).

Discussion

50.	What is the thickness of wafer in the alloy type transistors?(a) 1-2m inch(b) 3-5m inch(c) 5-6m inch(d) 4-7m inchThe question was asked by my school principal while I was bunking the class.Question is taken from Transistor Construction in portion Transistor Characteristics of Electronic Devices & Circuits
Answer» Correct ANSWER is (B) 3-5m inch Explanation: The wafer of crystal has a 3-5m inch thickness and 80m inch square. This is placed in a graphite jig with a dot of prepared indium. One dot of an indium is 3 TIMES LARGER than the other.

Discussion

Explore topic-wise InterviewSolutions in .

The CC configuration has an input resistance_________(a) 500kΩ(b) 750kΩ(c) 600kΩ(d) 400kΩI got this question in an internship interview.I would like to ask this question from The Common Collector Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits

What is the output resistance of CC transistor?(a) 25 Ω(b) 50 Ω(c) 100 Ω(d) 150 ΩI have been asked this question in an internship interview.My enquiry is from The Common Collector Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits

The base emitter voltage in a cut off region is_________(a) greater than 0.7V(b) equal to 0.7V(c) less than 0.7V(d) cannot be predictedI got this question in unit test.This question is from Transistor as a Switch in chapter Transistor Characteristics of Electronic Devices & Circuits

The output resistance is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VCE/∆ICI have been asked this question during an interview.Query is from The CE Characteristics in division Transistor Characteristics of Electronic Devices & Circuits

The AC current gain in a common base configuration is_________(a) -∆IC/∆IE(b) ∆IC/∆IE(c) ∆IE/∆IC(d) -∆IE/∆ICThe question was asked in unit test.My question is from The Common Base Configuration in chapter Transistor Characteristics of Electronic Devices & Circuits

The DC equivalent circuit for an NPN common emitter circuit is.I have been asked this question during an online interview.The question is from DC Load Lines topic in division Transistor Characteristics of Electronic Devices & Circuits

The input resistance in a CB transistor is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VEB/∆IEI have been asked this question in a job interview.The query is from The CB Characteristics in portion Transistor Characteristics of Electronic Devices & Circuits

Which of the following points locates the quiescent point?(a) (IC, VCB)(b) (IE, VCE)(c) (IE, VCB)(d) (IC, VCE)I got this question in semester exam.Question is taken from The CE Characteristics in chapter Transistor Characteristics of Electronic Devices & Circuits

The range of β is _________(a) 20 to 500(b) 50 to 300(c) 30 to 400(d) 10 to 20This question was addressed to me at a job interview.My query is from The Common Emitter Configuration topic in section Transistor Characteristics of Electronic Devices & Circuits

What is the melting point of indium in alloy type transistors?(a) 300°C(b) 200°C(c) 155°C(d) 100°CI have been asked this question in an online quiz.My doubt is from Transistor Construction topic in section Transistor Characteristics of Electronic Devices & Circuits

For the circuit shown, find the quiescent point.(a) (10V, 4mA)(b) (4V, 10mA)(c) (10V, 3mA)(d) (3mA, 10V)I had been asked this question in final exam.The doubt is from DC Load Lines topic in portion Transistor Characteristics of Electronic Devices & Circuits

When does the transistor act like an open switch?(a) cut off region(b) inverted region(c) saturated region(d) active regionThe question was asked during an interview.The query is from The Junction Transistor topic in chapter Transistor Characteristics of Electronic Devices & Circuits

The input resistance is given by _________(a) ∆VCE/∆IB(b) ∆VBE/∆IB(c) ∆VBE/∆IC(d) ∆VBE/∆IEI got this question during an online interview.I would like to ask this question from The CE Characteristics topic in division Transistor Characteristics of Electronic Devices & Circuits

The relation between α and β is_________(a) β = α/ (1-α)(b) α = β/(1+β)(c) β = α/ (1+α)(d) α = β/(1- β)The question was asked in a job interview.The query is from The Common Emitter Configuration topic in portion Transistor Characteristics of Electronic Devices & Circuits

The larger dot of the indium is used as_________(a) base(b) emitter(c) control pin(d) collectorThis question was addressed to me in my homework.This interesting question is from Transistor Construction in portion Transistor Characteristics of Electronic Devices & Circuits

In a PNP germanium transistor, the cut in voltage is about_________(a) -0.1V(b) -0.01V(c) -0.05V(d) -0.07VThis question was addressed to me in exam.Asked question is from The Transistor as an Amplifier topic in section Transistor Characteristics of Electronic Devices & Circuits

The amplification factor for a transistor is given by_________(a) A=αRL/re(b) A=αRLre(c) A=re/ αRL(d) A=RL/reαThis question was posed to me in an interview for job.The question is from The Transistor as an Amplifier topic in portion Transistor Characteristics of Electronic Devices & Circuits