Power Electronics Question & Answers July 7, 2021 By WatElectronics 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. Electrical Mechanical Solar All the above Hint 2). Modern type power electronic converters are ____ spectrum type of application. Broad Narrow Both a and b None of the above Hint 3). Which of the following are the examples of broad spectrum application? Active power filters Switched type mode power supplies Electrical machine motor control All the above Hint 4). Power electronics is an application of ____ state electronics, whose function is to control and conversion of electric power. Solid Liquid Gaseous None of the above Hint 5). Which of the following are the applications of power electronics? Battery charger HVDC thyristor PC’s power supply All the above Hint 6). A thyristor is a ______ device. Semiconductor Conducting Insulating All the above Hint 7). Which of the following is the first high power electronic device? Mercury arc valves Thermistors Transformers All the above Hint 8). Mercury arc valves is also called as __________. Mercury vapor Mercury vapor rectifier Mercury arc rectifier Both b and c Hint 9). Mercury vapor rectifier is an _____ rectifier. Electrical Mechanical Electronic All the above Hint 10). Mercury vapor rectifier converts ______ into DC current. High voltage High AC current Either a or b Low voltage Hint 11). Mercury vapor rectifier is a ______ type of tube. Cold cathode gas filled Warm cathode gas filled Cold anode Liquid filled Hint 12). Mercury vapor rectifier contains mercury in ______ state. Liquid Solid Gaseous None of the above Hint 13). Mercury vapor rectifier has a capacity to carry _____ value current. Higher Lower Zero Much higher Hint 14). Mercury vapor rectifier is invented by _____ in the year 1902. Peter Cooper Hewitt Henry Michele Richard Hint 15). The purpose of mercury vapor rectifier is ________. Provides power to industrial motors Provides power to electric railway Provides power to streetcars All the above Hint 16). Modern power electronic devices use ____ and _____ to perform energy conversion. Semiconductor device and power transistors Conductor device and power transistors Semiconductor device and transistors All the above Hint 17). The conductivity value of a semiconductor device is ________. Infinity Below conductors conductivity value Above insulator conductivity value Between conductor and insulator conductivity value Hint 18). Which of the following are the examples of a conducting materials? Copper Water Oil Both a and b Hint 19). A conducting material _____ the current flow. Blocks Allows Partially allows Partially blocks Hint 20). An insulator _____ the current flow. Blocks Allows Partially allows Partially blocks Hint 21). An semiconducting material ____ the current flow. Blocks Allows Partially allows Partially blocks Hint 22). A semiconducting device is classified into how many types? 2 3 1 4 Hint Read more about Semi-conductors. 23). How many configuration does a semiconducting device has? 2 3 1 4 Hint 24). A P-type semiconductor has majority of _______ charge carriers. Electrons Holes Both a and b Partial electrons and partial holes Hint Read more about P-Type Semiconductor. 25). A N-type semiconductor has majority of _____ charge carriers. Electrons Holes Both a and b Partial electrons and partial holes Hint Read more about N-Type Semiconductor. 26). Which of the following are the examples of a inducting materials? Copper Water Oil Both a and b Hint 27). The process of adding impurities to the semiconducting material is called. Doping Adding Oxidizing None of the above Hint 28). Which of the following are charge carrier? Holes Electrons Neutrons Both a and b Hint 29). Which of the following are the examples of semiconductor device? Diodes Thyristors Power transistors Both a and b Hint 30). Which of the following are the examples of Power transistors device? Diodes IGBT MOSFET Both b and c Hint Power Electronics Exam Questions & Answers 31). A diode has _____ number of terminals. 2 3 1 5 Hint Read more about Diodes. 32). A diode conducts in how many directions? Uni-direction Bi direction Vertical direction Multiple direction Hint 33). A thermionic diode is also called as ______. Vacuum bulb Vacuum tube Gas tube None of the above Hint 34). Which of the following are the components of a vacuum tube? Heated cathode Anode Heater Glass tube All the above Hint 35). A diode allows current to flow in _____ direction. Forward Backward Bidirectional None of the above Hint 36). A diode blocks the current to flow in _____ direction. Forward Reverse Bidirectional None of the above Hint 37). The unidirectional behavior of a diode is called as ________. Rectification Amplification Modulation Transmission Hint 38). A rectification of a diode converts ____ current into ___ current. AC to DC DC to AC AC to AC DC to DC Hint 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? Forward Reverse Both a and b None of the above Hint 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? Forward Reverse Both a and b None of the above Hint 40). Positive polarity is represented as ________. +ve –ve Both a and b Either a or b Hint 41). Negative polarity is represented as ________. +ve –ve Both a and b Either a or b Hint 42). MOSFET stands for _______. Metal oxide semiconductor field effect transistor Metal oxide semiconductor field effect thyristor Metal oxide semiconductor field efficient transistor None of the above Hint Read more about MOSFET. 43). IGBT stands for _______. Insulated gate bipolar transistor Independent gate bipolar transistor Insulated gate bipolar thermometer None of the above Hint 44). The main advantage of MOSFET is _______. Provides resistance Handles high power Is an open circuit system None of the above Hint 45). Power conversion systems are classified based on input- output ____ parameter. Current Voltage Power None of the above Hint 46). Which of the following are the examples of power conversion systems? DC to AC inverter AC to DC rectifier DC to DC converter All the above Hint 47). AC or DC rectifier are used in _____ electronic devices. TV Personal computer Battery chargers All the above Hint 48). In power electronic device the power ranges from ___watts to ___ watts. Tens to hundred One to ten Ten to thousand None of the above Hint 49). The device that is used to control the speed of induction motor is called ______. Variable speed drive Tachometer Pyrometer None of the above Hint 50). VSD in power electronics stands for _______. Variable speed drive Vary speed drive Variable silent drive Variable speed diode Hint 51). In VSD the power ranges from _____ watts to ____ watts. Few 100’s Watts to 10’s of mega Watts Few 10’s Watts to 100’s of mega Watts Few 1 Watt to 10’s of mega Watts None of the above Hint 52). Power is expressed in terms of _____ units. Watts Meters Ohms Hertz Hint 53). Rectifier converts ___ into ___ to allow the current to pass in single direction. AC to DC DC to AC AC to AC DC to DC Hint Read more about Rectifier. 54). An inverter converts ___ into ___ to allow the current to pass in single direction. AC to DC DC to AC AC to AC DC to DC Hint 55). Do inverters produce power? Yes No Maybe Hint 56). A power inverter is a combination of ___ and ___. Electronic circuitry and mechanical rotatory apparatus Power and current source Transformer and electronic circuitry None of the above Hint 57). Power inverters are used in which type of applications? Mechanical power application Electrical power application Electronic power applications None of the above Hint 58). Which type of power inverters use rotatory apparatus? Static Dynamic Both a and b None of the above Hint 59). Which type of power inverters use stationary apparatus? Static Dynamic Both a and b None of the above Hint 60). Power inverters in electrical power appliances are used in ___ current and voltage conditions. High Low Medium Zero Hint 61). Power inverters in electronic power appliances are used in ___ current and voltage conditions. High Low Medium Zero Hint 62). An oscillator uses _____ current and voltage range in circuit. High Low Medium Zero Hint 63). An ADC converter converts ______ to _______. AC to DC DC to AC AC to AC DC to DC Hint 64). A DAC converter converts ________ to ________. AC to DC DC to AC AC to AC DC to DC Hint 65). An electronic device that produces periodic oscillation is called ________. Oscillator Resistor Rectifier Inverter Hint 66). The output wave of an oscillator is in _____ form. Square Triangle Sinusoidal All the above Hint 67). An oscillator converts ______ to ________. AC to DC DC to AC AC to AC DC to DC Hint 68). Which of the following are the applications of an oscillator? Clocks Calculators Computers All the above Hint 69). Which of the following are the application of power electronic devices? Thyratron Ignitron Mercury arc valve All the above Hint 70). Which of the following are the examples of triggered devices in power electronics? Thyratron Ignitron Mercury arc valve Both a and b Hint Power Electronics MCQs with Answers 71). A thyratron is filled with _____ type inside a glass tube. Gas Water Liquid None of the above Hint 72). A thyratron is used as high power electrical type _____ and ____ type rectifier. Switch, controlled Resistor, uncontrolled Amplifier, zero None of the above Hint 73). A condition where gas gets ionized and electrons multiply is called _____. Townsend discharge Cathode discharge Anode discharge None of the above Hint 74). Which type of gasses are used in thyratron? Hydrogen Neon Xenon All the above Hint 75). Can thyratron tube linearly amplify signals? Yes No Maybe Hint 76). Which of the following are the components of a thyratron tube? Anode Hot Cathode One or more control grids All the above Hint 77). The thyratron tube filled with deuterium is at ____ pressure. 300 to 500, Torr 200 to 500, Torr 300 to 700, Torr 300 to 900, Torr Hint 78). A commercial thyratrons contains _______ type reservoir. Titanium hydride Pentium hydride Tetradone hydride None of the above Hint 79). Which of the following are the applications of thyratron tube? Incandescent lamp Solenoids Dekatron calculators All the above Hint 80). Which of the following are the applications of small thyratron tube? Incandescent lamp Solenoids Dekatron calculators 885 triode thyratron Hint 81). 885 triode thyratron tube is filled with _______ gas. Argon Helium Neon None of the above Hint 82). 885 triode thyratron is used in _____ type of circuits to provide oscilloscopes at early stage. Time base Frequency base Amplitude base None of the above Hint 83). 885 triode thyratron was designed in which year _______. 1930 1980 1931 1990 Hint 84). The application of 885 triode thyratron is ________. Battery chargers Light dimmers Solar panels Both a and b Hint 85). The 885 triode thyratron requires minimum of _____ voltage to operate. 2.5V 2.0V 1V 5V Hint 86). The 885 triode thyratron has ______ number of pins. 2 3 4 5 Hint 87). Which of the following are the simulation software for a power electronic circuits? MATHLAB PSIM PLECS All the above Hint 88). The application of a DC/DC type converters is ________. Mobile phone PDA Wind turbines All the above Hint 89). DC/DC type converters has _____ type voltage. Fixed Variable Zero None of the above Hint 90). The applications of a AC/DC type converters are _______. Computers Television Wind turbines Both a and b Hint 91). The applications of a AC/AC type converters are _______. Light dimmer International power adapters Wind turbines Both a and b Hint 92). AC/AC converters in power distribution networks use ____ range of frequency. 50 Hz to 60 Hz 60 Hz to 70 Hz 40 Hz to 60 Hz 10 Hz to 60 Hz Hint 93). The applications of a DC/AC type converters are ________. Uninterruptible power supply Renewable energy Computers Both a and b Hint 94). DC/AC type converters are also known as ________. Inverter Amplifier Rectifier None of the above Hint 95). AC/DC type converters are also known as ________. Inverter Amplifier Rectifier None of the above Hint 96). Which of the following are the applications of motor driver? Pumps Bowlers Mill drivers All the above Hint 97). Mill drivers are used in which applications? Paper Textile Cement All the above Hint 98). In power electronics hybrid electric vehicles are used in how many formats? 2 3 4 5 Hint 99). HEV’s application in power electronics stands for _______. Hybrid electric vehicles Hybrid electronic vehicles High electric vehicles None of the above Hint 100). ICE in power electronics stands for _______. Internal combustion engine Internal control engine Internal combustion engineer None of the above Hint Power Electronics Interview Questions & Answers 101). How many diodes are required to construct a half-wave rectifier? 1 2 3 4 Hint 102). What is form factor(F.F) of half wave rectifier? F.F=Average value / peak value F.F=Average value/dc output voltage F.F=Average value/ac input voltage F.F=R.M.S value/Average value Hint 103). Half wave rectifier is used to convert _____ voltage to ______ voltage. Half of the ac cycle into pulsating dc Ac into dc Dc into ac Full ac cycle into pulsating dc Hint 104). The flow of current in a half-wave rectifier is ______. No direction One direction Two directions None Hint 105). What is the equation ripple factor of a half-wave rectifier? (Vrms/V DC ) 2 Γ=√(Vdc/Vrms) Vdc Γ=√(Vrms/Vdc)2 -1 Hint 106). What is the efficiency of a half-wave rectifier? P dc /P ac 0 1 η = Pdc/Pac Hint 107). What happens to the diode of half-wave rectifier when peak inverse voltage is high? Diode will work in a good position Diode will be destroyed Both a and b None Hint 108). From below given options select the best suitable applications of half-wave rectifier. For rectification applications For signal demodulation applications For signal peak applications All of the above Hint 109). What is the ripple factor of half wave rectifier? 1.2 1.20 1.12 1.21 Hint 110). What is the efficiency of half wave rectifier? 20.4% 70.6% 45.2% 40.6% Hint 111). What is the drawback of a half-wave rectifier? High efficiency Medium efficiency Low efficiency Infinite efficiency Hint 112). Which of the following are full-wave rectifiers? Center tap full wave rectifier Full-wave bridge rectifier Both a and b Bridge rectifier Hint 113). What is the transformer utilization factor of a full-wave rectifier? 0.99 0.23 0.693 0.22 Hint 114). What is the transformer utilization factor of a half-wave rectifier? 0.22 0.26 0.44 0.287 Hint 115). Full wave rectifier is used to convert _______ to ______. Ac cycle to Dc Dc cycle to Ac Ac cycle into pulsating Dc Dc cycle into pulsating Ac Hint 116). What is the peak factor of a full-wave rectifier? KP = RMS value/form factor KP =0 KP=1 KP=Peak value of current/RMS value of current Hint 117). Half wave rectifier is called as ________. Uni- directional Bi-directional Both a and b None Hint Read more about Half Wave Rectifier. 118). Full wave rectifier is called as _________. Uni-directional Bi-directional Zero direction Multi-directions Hint Read more about Full Wave Rectifier. 119). How many components used in a half-wave rectifier? 2 4 5 6 Hint 120). How many components used in a full-wave rectifier? 1 4 3 2 Hint 121). Which of the following are the electrical and electronic components used in power electronic devices? Resistor Inductor Capacitor All the above Hint 122). Which of the following are the semiconductor components used in power electronic devices? Diodes Transistors FETS All the above Hint 123). FET stands for ______. Field Effect Transistor Field Efficient Transistor Field Effective Transistor Field Effect Transformer Hint Read more about FET. 124). What are the 3 branches of that an power electronics combines any two branches? System and control Electronics and devices Power and energy All the above Hint 125). System and control includes which of the following? Switch control Feedback control Power supply Both a and b Hint 126). Electronics and devices includes of the following? Switch control Feedback control Both a and b None of the above Hint 127). Power and energy includes which of the following. Energy processing Power supply Motor and drivers All the above Hint 128). Conversion of energy occurs in which form? AC to AC AC to DC DC to DC All the above Hint 129). Units of resistor are ________. Hertz Centimeters Ohms Columb’s Hint 130). Units of capacitor are _______. Henry Centimeters Ohms Columb’s Hint Read more about Capacitor. 131). What is a DAC converter? Analog converter Digital converter Analog to digital converter Digital to analog converter Hint 132). What does a DAC consist of? Binary type inputs and a single output Digital type input and multi outputs 1-binary type input and 2 outputs 2-binary type input and 1 output Hint 133). Name the types of DAC. Weighted resistor DAC R-2R Ladder DAC Both a and b None Hint 134). What is the other name of binary resistor DAC? R-2R DAC Weighted resistor DAC Digital resistor DAC None Hint 135). What is the disadvantage of Weighted Resistor DAC? No of bits present in the digital input increases. No of bits present in the digital input decreases No of bits present in the digital input are constant None Hint 136). Where are DAC used? Mobiles Television Music players All the above Hint 137). High-speed DACs are used in _______. Mobile communications T.V. Satellite None Hint 138). Ultra high-speed DAC are used in _____. Optical fiber Optical communications Sensors Both a and c Hint 139). What are the applications of DAC? Audio Video Motor control All of the above Hint 140). Give the resolution equation for n bit DAC. 2n 2a 9n 2n Hint 141). What will happen to DAC when we increase its resolution. Increases Decreases Constant None Hint 142). What is the error related to DAC? Nonmonotonic and offset error Offset error Ripple error None Hint 143). What is the real use of binary type weighted digital to analog converters? 4-bit of D/A type converters 8-bit of D/A type converters Both a and b None Hint 144). Which of the following is R-2R type Ladder DAC advantage? Only two resistors Three resistors N-resistors None Hint 145). Give the step size equation for DAC. 2n 2n/Range Range-2n Range/2n Hint Time is Up! Time's up
