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Power Electronics Question & Answers

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This article lists 100 Power Electronics MCQs for engineering students. All the Power Electronics Questions & Answers given below includes solution and link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up their fundamentals on Power Electronics topic which is core in Electrical Engineering.

In electrical engineering, a branch that deals with the conversion of power from one form to another form is Power Electronics. It uses electronic and electrical components like resistors, inductors, semiconductor devices (like diodes, thyristors, FET’s, IGBT, etc), capacitors, and various other components during the conversion of the power in equipment.

Power electronics combines any of the 2 branches out of 3 branches. The 3 branches are System and control that consist of switch control and feedback control, the second branch is electronics and devices which contain circuits, power semiconductors, and magnetics, the third one is power and energy which contains energy processing, power supply, motor, and drivers.

Conversion of energy occurs in any form like AC to AC, also known as Cyclo converters, DC to DC also known as converters, DC to AC know as inverters and AC to DC called as rectifiers.

A few of the applications of power electronics are biomedical applications, textile industries, DC motors, car batteries, mobile phones, and many more.

1). Power electronics converts ________ energy into another form of energy.
HintPower electronics converts electrical energy into another form of energy.
2). Modern type power electronic converters are ____ spectrum type of application.
HintModern type power electronic converters are a broad-spectrum type of applications.
3). Which of the following are the examples of broad spectrum application?
HintExamples of broad-spectrum applications are Active power filters Switched type mode power supplies and Electrical machine motor control.
4). Power electronics is an application of ____ state electronics, whose function is to control and conversion of electric power.
HintPower electronics is an application of solid-state electronics, whose function is to control and conversion of electric power.
5). Which of the following are the applications of power electronics?
HintThe applications of power electronics are Battery charger HVDC thyristor PC’s power supply.
6). A thyristor is a ______ device.
HintA thyristor is a semiconductor device.
7). Which of the following is the first high power electronic device?
HintThe first high-power electronic device is Mercury arc valves.
8). Mercury arc valves is also called as __________.
HintMercury arc valves are also called Mercury vapor rectifier and Mercury arc rectifier.
9). Mercury vapor rectifier is an _____ rectifier.
HintMercury vapor rectifier is an Electrical rectifier.
10). Mercury vapor rectifier converts ______ into DC current.
HintMercury vapor rectifier converts either high voltage or high AC current into DC current.
11). Mercury vapor rectifier is a ______ type of tube.
HintMercury vapor rectifier is a Cold cathode gas-filled type of tube.
12). Mercury vapor rectifier contains mercury in ______ state.
HintMercury vapor rectifier contains mercury in the liquid state.
13). Mercury vapor rectifier has a capacity to carry _____ value current.
HintMercury vapor rectifier has a capacity to carry a much higher value current.
14). Mercury vapor rectifier is invented by _____ in the year 1902.
HintMercury vapor rectifier is invented by Peter Cooper Hewitt in the year 1902.
15). The purpose of mercury vapor rectifier is ________.
HintThe purpose of the mercury vapor rectifier is to provide power to the electric railway, industrial motors, and streetcars.
16). Modern power electronic devices use ____ and _____ to perform energy conversion.
HintModern power electronic devices use semiconductor devices and power transistors to perform energy conversion.
17). The conductivity value of a semiconductor device is ________.
HintThe conductive value of a semiconductor device lies between conductor and insulator conductivity value.
18). Which of the following are the examples of a conducting materials?
HintExamples of conducting materials are copper and water.
19). A conducting material _____ the current flow.
HintA conducting material allows the current flow.
20). An insulator _____ the current flow.
HintAn insulator blocks the current flow.
21). An semiconducting material ____ the current flow.
HintA semiconducting material partially allows the current flow depending on the type of semiconductor used.
22). A semiconducting device is classified into how many types?
HintA semiconducting device is classified into 2 types namely P-type and N-type.
Read more about Semi-conductors.
23). How many configuration does a semiconducting device has?
HintA semiconducting device has 2 types of configuration namely NPN and PNP type.
24). A P-type semiconductor has majority of _______ charge carriers.
HintA P-type semiconductor has a majority of holes as charge carriers.
Read more about P-Type Semiconductor.
25). A N-type semiconductor has majority of _____ charge carriers.
HintAn N-type semiconductor has the majority of electrons as charge carriers.
Read more about N-Type Semiconductor.
26). Which of the following are the examples of a inducting materials?
HintAn example of an inducting material is oil, which blocks the flow of current.
27). The process of adding impurities to the semiconducting material is called.
HintThe process of adding impurities to the semiconducting material is called doping.
28). Which of the following are charge carrier?
HintBoth holes (+ve) and electrons (-ve) are the charge carriers.
29). Which of the following are the examples of semiconductor device?
HintExamples of semiconductor devices are Thyristors and diodes.
30). Which of the following are the examples of Power transistors device?
HintExamples of power transistors devices are IGBT and MOSFET.

Power Electronics Exam Questions & Answers

31). A diode has _____ number of terminals.
HintA diode has 2 number of terminals, a positive and a negative terminal.
Read more about Diodes.
32). A diode conducts in how many directions?
HintA diode conducts in uni-direction.
33). A thermionic diode is also called as ______.
HintA thermionic diode is also called a vacuum tube.
34). Which of the following are the components of a vacuum tube?
HintThe components of a vacuum tube are a heated cathode anode, heater, and glass tube.
35). A diode allows current to flow in _____ direction.
HintA diode allows current to flow in forward direction.
36). A diode blocks the current to flow in _____ direction.
HintA diode blocks the current flow in the reverse direction.
37). The unidirectional behavior of a diode is called as ________.
HintThe unidirectional behavior of a diode is called rectification.
38). A rectification of a diode converts ____ current into ___ current.
HintRectification of a diode converts AC current into DC current.
38). When a positive polarity of battery is connected to the positive terminal of diode and a negative polarity of battery is connected to the negative terminal of diode it is called ____ bias?
HintWhen a positive polarity of the battery is connected to the positive terminal of the diode and the negative polarity of the battery is connected to the negative terminal of diode it is called forward bias.
39). When a positive polarity of battery is connected to the negative terminal of diode and a negative polarity of battery is connected to the positive terminal of diode it is called ___ bias?
HintWhen a positive polarity of the battery is connected to the negative terminal of the diode and the negative polarity of the battery is connected to the positive terminal of the diode it is called reverse bias.
40). Positive polarity is represented as ________.
HintPositive polarity is represented as “+”.
41). Negative polarity is represented as ________.
HintThe negative polarity is represented as “-”.
42). MOSFET stands for _______.
HintMOSFET stands for metal oxide semiconductor field-effect transistor.
Read more about MOSFET.
43). IGBT stands for _______.
HintIGBT stands for Insulated gate bipolar transistor.
44). The main advantage of MOSFET is _______.
HintThe main advantage of MOSFET is it handles high power.
45). Power conversion systems are classified based on input- output ____ parameter.
HintPower conversion systems are classified based on input-output power parameters.
46). Which of the following are the examples of power conversion systems?
HintExamples of power conversion systems are DC to AC inverter AC to DC rectifier DC to DC converter.
47). AC or DC rectifier are used in _____ electronic devices.
HintAC or DC rectifiers are used in electronic devices like personal computers, TV and battery chargers.
48). In power electronic device the power ranges from ___watts to ___ watts.
HintIn power electronic device power ranges from tens to several hundreds of watts.
49). The device that is used to control the speed of induction motor is called ______.
HintThe device that is used to control the speed of the induction motor is called a variable speed drive.
50). VSD in power electronics stands for _______.
HintVSD in power electronics stands for variable speed drive.
51). In VSD the power ranges from _____ watts to ____ watts.
HintIn VSD the power ranges from Few 100’s Watts to 10’s of mega Watts.
52). Power is expressed in terms of _____ units.
HintPower is expressed in terms of watts units.
53). Rectifier converts ___ into ___ to allow the current to pass in single direction.
HintA rectifier converts AC into DC to allow the current to pass in a single direction.
Read more about Rectifier.
54). An inverter converts ___ into ___ to allow the current to pass in single direction.
HintAn inverter converts DC into AC to allow the current to pass in a single direction.
55). Do inverters produce power?
HintNo, inverters don't produce power.
56). A power inverter is a combination of ___ and ___.
HintA power inverter is a combination of electronic circuitry and mechanical rotatory apparatus.
57). Power inverters are used in which type of applications?
HintPower inverters are used in electrical power type of applications.
58). Which type of power inverters use rotatory apparatus?
HintA static type of power inverters uses rotatory apparatus.
59). Which type of power inverters use stationary apparatus?
HintA dynamic type of power inverters use stationary apparatus.
60). Power inverters in electrical power appliances are used in ___ current and voltage conditions.
HintPower inverters are used in high current and voltage conditions.
61). Power inverters in electronic power appliances are used in ___ current and voltage conditions.
HintPower inverters in electronic power appliances are used in low current and voltage conditions.
62). An oscillator uses _____ current and voltage range in circuit.
HintAn oscillator uses low current and voltage range in a circuit.
63). An ADC converter converts ______ to _______.
HintAn ADC converter converts AC to DC.
64). A DAC converter converts ________ to ________.
HintA DAC converter converts DC to AC.
65). An electronic device that produces periodic oscillation is called ________.
HintAn electronic device that produces periodic oscillation is called an oscillator.
66). The output wave of an oscillator is in _____ form.
HintThe output wave of an oscillator can be of square or triangle or a sinusoidal wave form.
67). An oscillator converts ______ to ________.
HintAn oscillator converts DC to AC.
68). Which of the following are the applications of an oscillator?
HintOscillators are used in applications like clocks, computers and calculators.
69). Which of the following are the application of power electronic devices?
HintThe application of power electronic devices are thyratron, Mercury arc valve, and ignitron.
70). Which of the following are the examples of triggered devices in power electronics?
HintThe examples of triggered devices in power electronics are ignitron and thyratron.

Power Electronics MCQs with Answers

71). A thyratron is filled with _____ type inside a glass tube.
HintA thyratron is filled with gas inside a glass tube.
72). A thyratron is used as high power electrical type _____ and ____ type rectifier.
HintA thyratron is used as a high-power electrical type switch and controlled type rectifier.
73). A condition where gas gets ionized and electrons multiply is called _____.
HintA condition where gas gets ionized and electrons multiply is called Townsend discharge.
74). Which type of gasses are used in thyratron?
HintThe gasses are used in the thyratron vacuum tube are hydrogen, xenon, and neon.
75). Can thyratron tube linearly amplify signals?
HintNo thyratron tube cannot linearly amplify signals.
76). Which of the following are the components of a thyratron tube?
HintThe components of a thyratron tube anode, filament, hot cathode, and one or more control grids.
77). The thyratron tube filled with deuterium is at ____ pressure.
HintThe thyratron tube filled with deuterium is compressed at 300 to 500, Torr pressure.
78). A commercial thyratrons contains _______ type reservoir.
HintA commercial thyratrons contains a titanium hydride type reservoir.
79). Which of the following are the applications of thyratron tube?
HintThe applications of thyratrons tube are incandescent lamp Solenoids and dekatron calculators.
80). Which of the following are the applications of small thyratron tube?
HintThe applications of small thyratron tube is 885 triode thyratron.
81). 885 triode thyratron tube is filled with _______ gas.
Hint885 triode thyratron tube is filled with Argon gas.
82). 885 triode thyratron is used in _____ type of circuits to provide oscilloscopes at early stage.
Hint885 triode thyratron is used in the time-based types of circuits to provide oscilloscopes at an early stage.
83). 885 triode thyratron was designed in which year _______.
Hint885 triode thyratron is designed in 1930.
84). The application of 885 triode thyratron is ________.
HintThe application of 885 triode thyratron is light dimmers and battery chargers.
85). The 885 triode thyratron requires minimum of _____ voltage to operate.
HintThe 885 triode thyratron requires a minimum of 2.5 voltage to operate.
86). The 885 triode thyratron has ______ number of pins.
HintThe 885 triode thyratron has 5 number of pins.
87). Which of the following are the simulation software for a power electronic circuits?
HintThe simulation software for power electronic circuits are MATHLAB, PSIM, and PLECS.
88). The application of a DC/DC type converters is ________.
HintThe applications of DC/DC type converters are, PDA, mobile phones, and wind turbines.
89). DC/DC type converters has _____ type voltage.
HintDC/DC type converters have fixed type voltage.
90). The applications of a AC/DC type converters are _______.
HintThe applications of AC/DC type converters are television and computers.
91). The applications of a AC/AC type converters are _______.
HintThe application of AC/AC type converters is light dimmer and international power adaptors.
92). AC/AC converters in power distribution networks use ____ range of frequency.
HintAC/AC converters in power distribution networks use a 50 Hz to 60 Hz range of frequency.
93). The applications of a DC/AC type converters are ________.
HintThe application of DC/AC type converters is an uninterruptable power supply and renewable energy.
94). DC/AC type converters are also known as ________.
HintDC/AC type converters are also known as inverters.
95). AC/DC type converters are also known as ________.
HintAC/DC type converters are also known as rectifiers.
96). Which of the following are the applications of motor driver?
HintThe applications of the motor driver are mill drivers, bowlers, and pumps.
97). Mill drivers are used in which applications?
HintMill drivers are used in industries like paper, textile, and cement.
98). In power electronics hybrid electric vehicles are used in how many formats?
HintIn power electronics hybrid electric vehicles are used in 2 formats namely parallel hybrid and series hybrid.
99). HEV’s application in power electronics stands for _______.
HintHEV’s application in power electronics stands for hybrid electric vehicles.
100). ICE in power electronics stands for _______.
HintICE in power electronics stands for internal combustion engine.

Power Electronics Interview Questions & Answers

101). How many diodes are required to construct a half-wave rectifier?
HintOnly one diode is required to construct a half-wave rectifier.
102). What is form factor(F.F) of half wave rectifier?
HintF.F=R.M.S value/Average value.
103). Half wave rectifier is used to convert _____ voltage to ______ voltage.
HintA half wave rectifier is used to convert half of the ac cycle into pulsating dc voltage.
104). The flow of current in a half-wave rectifier is ______.
HintDiodes only allow current to flow in one direction.
105). What is the equation ripple factor of a half-wave rectifier?
HintThe ripple factor of a half-wave rectifier equation is Γ=√(Vrms/Vdc)2 -1
106). What is the efficiency of a half-wave rectifier?
HintThe efficiency of a half-wave rectifier is η = Pdc/Pac.
107). What happens to the diode of half-wave rectifier when peak inverse voltage is high?
HintWhen the diode of half-wave rectifier when peak inverse voltage is diode will be destroyed.
108). From below given options select the best suitable applications of half-wave rectifier.
HintThe applications of half-wave rectifiers are rectification applications for signal demodulation applications and for signal peak applications.
109). What is the ripple factor of half wave rectifier?
HintThe ripple factor of the half wave rectifier is 1.21
110). What is the efficiency of half wave rectifier?
HintThe efficiency of the half-wave rectifier is 40.6%.
111). What is the drawback of a half-wave rectifier?
HintThe drawback of a half-wave rectifier is low-efficiency.
112). Which of the following are full-wave rectifiers?
HintThe full-wave rectifier are center tap full-wave rectifier, full-wave bridge rectifier.
113). What is the transformer utilization factor of a full-wave rectifier?
HintThe transformer utilization factor of a full-wave rectifier 0.693
114). What is the transformer utilization factor of a half-wave rectifier?
HintThe transformer utilization factor of a half-wave rectifier is 0.287.
115). Full wave rectifier is used to convert _______ to ______.
HintA full-wave rectifier is used to convert the entire Ac cycle into pulsating Dc.
116). What is the peak factor of a full-wave rectifier?
HintThe peak factor (Kp) of the full-wave rectifier is the ratio between the peak value of current and the RMS value of current.
117). Half wave rectifier is called as ________.
HintThe Half-Wave Rectifier is a unidirectional rectifier; it means it will allow the conduction in one direction only. That’s why either it can convert positive half only or negative half only into DC voltage.
Read more about Half Wave Rectifier.
118). Full wave rectifier is called as _________.
HintA full-wave Rectifier is a bi-directional rectifier. It conducts for the positive half as well as the negative half of the cycle.
Read more about Full Wave Rectifier.
119). How many components used in a half-wave rectifier?
Hint1 diode and one step down transformer components are used in a half-wave rectifier.
120). How many components used in a full-wave rectifier?
Hint2 diodes and one step-down transformer are the components used in a full-wave rectifier.
121). Which of the following are the electrical and electronic components used in power electronic devices?
HintThe electrical and electronic components used in power electronic devices are capacitors, resistors, and inductors.
122). Which of the following are the semiconductor components used in power electronic devices?
HintThe semiconductor components used in power electronic devices are Diodes, FETs, transistors.
123). FET stands for ______.
HintFET stands for Field Effect Transistor.
Read more about FET.
124). What are the 3 branches of that an power electronics combines any two branches?
HintThe 3 branches of that a power electronics combines any two system and control, electronics and devices and power and energy.
125). System and control includes which of the following?
HintSystem and control include switch control and feedback control.
126). Electronics and devices includes of the following?
HintElectronics and devices include circuits, power semiconductors, and magnetics.
127). Power and energy includes which of the following.
HintPower and energy include energy processing, power supply, and motor and drivers.
128). Conversion of energy occurs in which form?
HintConversion of energy occurs in any of the 4 forms like AC to AC, DC to DC, DC to AC, AC to AC.
129). Units of resistor are ________.
HintUnits of resistor are Ohms.
130). Units of capacitor are _______.
HintUnits of capacitor are henry.
Read more about Capacitor.
131). What is a DAC converter?
HintDAC is called a digital to analog converter.
132). What does a DAC consist of?
HintDAC consist of binary type input and a single output.
133). Name the types of DAC.
HintThere are two types of DAC’s namely Weighted resistor, DAC R -2R Ladder DAC.
134). What is the other name of binary resistor DAC?
HintThe other name of binary resistor DAC is weighted resistor DAC.
135). What is the disadvantage of Weighted Resistor DAC?
HintThe main disadvantage of weighted resistor DAC is no bits present in digital input increases.
136). Where are DAC used?
HintDAC is generally used in music players, T.V, mobiles.
137). High-speed DACs are used in _______.
HintThe use of high-speed DAC’s are in Mobile communications.
138). Ultra high-speed DAC are used in _____.
HintThe use of ultra-high-speed DAC’s is in optical communications systems.
139). What are the applications of DAC?
HintThe applications of DAC’s are in Audio, video, motor control.
140). Give the resolution equation for n bit DAC.
HintThe resolution equation for n-bit DAC is 2n.
141). What will happen to DAC when we increase its resolution.
HintThe increase in the resolution of DAC Decreases the step size.
142). What is the error related to DAC?
HintThe error related to DAC is a Nonmonotonic and offset error.
143). What is the real use of binary type weighted digital to analog converters?
HintThe use of binary type weighted DAC’s are in 8-bit D/A type converters.
144). Which of the following is R-2R type Ladder DAC advantage?
HintR-2R type Ladder DAC advantage is it has two resistor values R and 2R.
145). Give the step size equation for DAC.
HintThe step size equation for DAC is Range/2n.

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