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Basic Electronics Engineering Multiple Choice Questions UNIT I DIODE CIRCUITS 1.The process by which impurities are added to a pure semiconductor is a. Diffusing b. Drift c. Doping d. Mixing a. 5 eV b. 10 eV c. 15 eV d. 1 eV Ans: c 6.A semiconductor diode has forward resistance of the order of ………. a. Ω b. KΩ c. MΩ d. none of the above 2.When an atom gains or losses an ion it is said to be a. Ionised b. Bonded c. Excited d. stabilized Ans: a 3.Barrier potential for silicon diode a. 0.3 b. 0.4 c. 0.7 d. 0.1 Ans: d Ans: a 7.The reverse current in a diode is of the order of ……………. a. µA b. mA c. A d. KA Ans: a Ans: c 4.The manufacturer of diode provides the detail information about diode, in the form of a. excel sheet b. Data Sheet c. Log sheet d. None of above Ans: b 5. In a semiconductor, the energy gap between valence band and conduction band is about……… Sinhgad College of Engineering 8.A reverse-biased diode acts like a. open switch b. closed switch c. small resistance d. none of the above Ans: a 9.The potential barrier at a PN-junction is due to the charges on either side of the junction. These charges are….. a. minority carriers b. majority carriers c. both majority and minority carriers Page 1 Basic Electronics Engineering d. fixed donor and acceptor ions Ans: d 10.When we apply reverse bias to a junction diode, it a. lowers the potential barrier b. raises the potential barrier c. greatly increases the minority-carrier current d. greatly increases the majority-carrier current Ans: b 11.The turn-on voltage of a Ge junction diode is nearly….. volts. a. 0.7 b. 0.3 c. 1 d. 0.1 Ans: b 12.If a pure silicon crystal has one million free electrons inside it, how many holes does it have? a. One million b. two million c. zero d. ten million Ans: a 13.A strong electric field across a P-N junction that causes covalent bond to break apart is called a. avalanche breakdown b. reverse breakdown c. Zener Breakdown d. Low voltage break down Ans: c Sinhgad College of Engineering Multiple Choice Questions 14.Resistivity of semiconductor depends on… a. shape of the semiconductor b. atomic nature of semiconductor c. width of semiconductor d. length of semiconductor Ans : b 15.At room temperature, the current in the intrinsic semiconductor is due to.... a. Holes b. electrons c. Ions d. holes and electrons Ans : d 16.If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then a. The majority carrier density doubles b. the minority carrier density is doubled c. the minority carrier density becomes 4 times the original value d. both majority and minority carrier densities double Ans : c 17.When holes leave the p-material to fill electrons in the n-material the process is called a. Mixing b. Depletion c. Diffusion d. Depletion Ans : c 18.Diffusion current in the diode is caused by a. Chemical energy b. heat energy c. voltage Page 2 Basic Electronics Engineering Multiple Choice Questions d. crystal formation Ans: c Ans : a 19. Depletion region in a pn diode is due to a. reverse biasing b. forward biasing c. an area created by crystal doping d. an area void of current carriers 24.Reverse characteristic of diode is plotted in a. 1st Quadrant b. 2nd Quadrant c. 3rd Quadrant d. 4th Quadrant Ans: c Ans: a 20.When a diode is forward biased a. Barrier potential increases b. Barrier potential decreases c. Majority current reduces d. Minority current reduces Ans: b 21.The p-n junction forms device called a. Triac b. Diode c. multiplexer . d. Semiconductor Ans: b 22.The normal forward biased operation of diode is a. Below the knee point b. at the origin c. above knee point d. all the above Ans: c 23. In diode reverse current is due to a. Mobile donor ions b. Mobile acceptor ions c. minority carriers d. majority carriers Sinhgad College of Engineering 25.In an unbiased PN-junction, the junction current at equilibrium is a. due to diffusion of minority carriers only b. due to diffusion of majority carriers only c. zero, because equal but opposite carriers are crossing the junction d. zero, because no charges are crossing the junction Ans: c 26.In a PN-junction diode, holes diffuse from the P region to the N region because a. the free electrons in the N region attract them b. they are swept across the junction by the potential difference c. there is greater concentration of holes in the P region as compared to N region d. none of the above Ans: c 27.The number of minority carriers crossing the junction of a diode depends primarily on the a. concentration of doping impurities b. magnitude of the potential barrier c. magnitude of the forward-bias voltage d. rate of thermal generation of electron –hole pairs Page 3 Basic Electronics Engineering Multiple Choice Questions Ans: d 28.The forward bias applied to a PN- junction diode is increased from zero to higher values. Rapid increase in the current flow for a relatively small increase in voltage occurs a. immediately b. only after the forward bias exceeds the potential barrier c. when the flow of minority carriers is sufficient to cause an avalanche breakdown d. when the depletion area becomes larger than the space-charge area Ans: b 32.The ideal value of forward resistance of diode is a. high b. infinite c. zero d. very low Ans: c 33.Rectifier converts a. a.c. voltage to d.c.voltage b. a.c voltage to pulsating d.c voltage c. d.c voltage to a.c. voltage d. a.c voltage to a.c voltage 29.If the arrow of a semiconductor diode symbol is positive w.r.t. bar, then diode is…..biased. a. reverse b. forward c. none of the two d. forward or reverse Ans: b Ans: b Ans: b 30.The leakage current in a semiconductor diode is due to……. a. minority carriers b. majority carriers c. junction capacitance d. none of the above Ans: a 35.No. of diodes used in full wave rectifier is a. 1 b. 2 c. 3 d. 4 31.The ideal value of reverse resistance of diode is a. high b. infinite c. zero d. very low 36.In a full-wave rectifier, the current in each of the diodes flows for a. the complete cycle of the input signal b. half cycle of the input signal c. less than half cycle of the input signal d. zero time Ans: b Ans: b Sinhgad College of Engineering 34.Efficiency of half wave rectifier is a. 81.20% b. 40.60% c. 45.6 % d. 82.10% Ans: b Page 4 Basic Electronics Engineering Multiple Choice Questions 37.The peak value of the input to a half wave rectifier is 10V. the approximate peak value of the output is a. 10 V b. 3.18V c. 10.7V d. 9.3V 41.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V? a. 6.23 V b. 19.6 V c. 9.8 V d. 3.1 V Ans: d 38.The total secondary voltage in a centre tapped full wave rectifier is 125 V rms. Neglecting the diode drop, the rms output voltage is a. 125V b. 177V c. 100V d. 62.5V Ans: d 42.If Vm is the peak voltage across the secondary of the transformer in a half-wave rectifier(without any filter circuit. , then the maximum voltage on the reverse biased diode is a. Vm b. ½. Vm c. 2 Vm d. none of the above Ans: d Ans: a 39. a half-wave rectifier, the peak value of the ac voltage across the secondary of the transformer is 20√2 V. If no filter circuit is used, the maximum dc voltage across the load will be a. 28.28 V b. 14.14 V c. 20 V d. 9 V 43.If you are checking a 60 Hz full wave bridge rectifier and observe that the output has 60Hz ripple a. the circuit is working properly b. there is an open diode c. the transformer secondary is shorted d. the filter capacitor is leaky Ans: d Ans: b 40.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz? a. 60Hz b. 50Hz c. 120Hz d. this is impossible to determine 42.Efficiency of half wave rectifier is a. 81.20% b. 40.60% c. 45.60% d. 82.1 % Ans: c Sinhgad College of Engineering Ans: b 43.Ripple factor of full wave rectifier is a. 0.122 Page 5 Basic Electronics Engineering b. 0.4 c. 0.48 d. 0.05 Multiple Choice Questions c. 9.8 V d. 3.1 V Ans: d Ans: c 44.Efficiency of bridge rectifier is a. 81.2 % b. 40.6 % c. 45.60% d. 82.1 % Ans: a 48.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz? a. 60Hz b. 50 Hz c. 120 Hz d. this is impossible to determine 45.In an unbiased PN-junction, the junction current at equilibrium is a. due to diffusion of minority carriers only b. due to diffusion of majority carriers only c. zero, because equal but opposite carriers are crossing the junction d. zero, because no charges are crossing the junction Ans: c Ans: c Ans: a 46.If Vm is the peak voltage across the secondary of the transformer in a full-wave rectifier with a shunt capacitor filter circuit, then the maximum voltage on the reverse biased diode is a. Vm b. ½. Vm c. 2 Vm d. both A and B 50.What is the approximate dc output voltage from a filtered bridge rectifier whose peak output voltage is 30V? a. 19.1 V b. 9.5 V c. 30 V d. none of the above Ans: c 51.A half wave rectified sinusoidal waveform has a peak voltage of 12V. Its average value and rms value of the fundamental components are; respectively given by a. 15/p V, 7.5 V b. 20/p V, 10/Ö2 V c. 12/p V, 6 V 47.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V? a. 6.23 V b. 19.6 V Sinhgad College of Engineering 49.The output from an unfiltered half-wave or full wave rectifier is -a. a pulsating dc b. steady dc voltage c. smooth dc voltage d. none of the above Ans: c Page 6 Basic Electronics Engineering Multiple Choice Questions d. none of these Ans: c 52.In a bridge rectifier circuit we use a. no centre-tapping and diode having peak inverse voltage Vm b. no centre tapping and diode having inverse voltage 2Vm c. centre tapping and diode having reverse voltage Vm d. centre- tapping and diode having reverse voltage 2Vm 55. If Vm is the peak voltage across secondary of transformer in HWR (without any filter circuit. , then the maximum voltage on reverse biased diode is a. Vm b. 1/2Vm c. 2Vm d. none of the above Ans: a 53.A device converting a.c. to d.c. is called a. comparator b. inverter c. rectifier d. regulator 56. If Vm is the peak voltage across secondary of transformer in HWR ,if we use shunt capacitor filter, the maximum voltage that occurs on reverse biased diode is a. Vm b. 1/2Vm c. 2Vm d. none of the above Ans: c Ans: a 53. PIV rating of diode in a bridge rectifier is a. Vm b. 2Vm c. Vm/2 d. none of these 57.In Center tap FWR Vm is the peak voltage between center tap and one end of secondary, the maximum voltage that occurs on reverse biased diode is a. Vm b. 1/2Vm c. 2Vm d. none of the above Ans: a Ans: a 54.In HWR the peak value of ac voltage across secondary of transformer is 20√2 V if no filter circuit is used, the maximum d.c. voltage across the load will be a. 28.28 V b. 14.14 V c. 20 V d. 9 V Ans: c 58.In HWR the load current flows for a. the complete cycle of input signal. b. only for positive half cycle of input signal. c. less than half cycle of input signal. d. more than half cycle but lass than complete cycle of input signal. Ans: d Sinhgad College of Engineering Page 7 Basic Electronics Engineering Ans: b 59.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V? a. 6.23 V b. 19.6 V c. 9.8 V d. 3.1 V Ans : d Multiple Choice Questions 63.In a bridge rectifier circuit we use a. no centre-tapping and diode having peak inverse voltage Vm b. no centre tapping and diode having inverse voltage 2Vm c. centre tapping and diode having reverse voltage Vm d. centre- tapping and diode having reverse voltage 2Vm 60.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz? a. 60Hz b. 50 Hz c. 20 Hz d. this is impossible to determine Ans : a Ans: c Ans: b 61.In a full-wave rectifier, the dc load current equals 1A. How much dc current is carried by each diode? a. ½ A b. 1 A c. 2 A d. 0 A 65.The average value of a half wave rectified voltage with a peak value of 200V is a. 63.7V b. 127.3 V c. 141V d. 0V 64.In a full wave rectifier with R-C filter, the conduction angle a. 0 b. less than 180 c. Equal to 180 d. More than 0 Ans : a Ans: a 62.A half wave rectified sinusoidal waveform has a peak voltage of 12V. Its average value and rms value of the fundamental components are; respectively given by a. 15/p V, 7.5 V b. 20/p V, 10/Ö2 V c. 12/p V, 6 V d. none of these 66.When a 60 Hz sinusoidal voltage is applied to the input of a half wave rectifier, the output frequency is a. 120 Hz b. 30 Hz c. 60 Hz d. 0 Hz Ans : c Ans: c Sinhgad College of Engineering Page 8 Basic Electronics Engineering Multiple Choice Questions 67.The peak value of the input to a half wave rectifier is 10V. the approximate peak value of the output is a. 10 V b. 3.18 V c. 10.7 V d. 9.3 V 71.When the peak output voltage is 100V, the PIV for each diode in a centre- tapped full wave rectifier is( neglecting the diode drop. a. 100 V b. 200 V c. 141 V d. 50V Ans :d Ans : b 68.The average value of full wave rectified voltage with a peak value of 75V is a. 53 V b. 47.8 V c. 37.5 V d. 23.9 V 72.When the rms output voltage of a bridge full-wave rectifier is 20V, the peak –inverse voltage across the diodes is ( neglecting the diode drop. a. 20 V b. 40 V c. 28.3 V d. 56.6 V Ans :b 9.When a 60Hz sinusoidal voltage is applied to the input of a full wave rectifier, the output frequency is a. 120 Hz b. 60 Hz c. 240 Hz d. 0 V Ans : a 70.The total secondary voltage in a centre tapped full wave rectifier is 125 V rms. Neglecting the diode drop, the rms output voltage is a. 125V b. 177 V c. 100 V d. 62.5 V Ans : c 73.A 60 V peak full wave rectified voltage is applied to a capacitor input filter. If f=120 Hz, RL =10K a. 0.6 V b. 6 mV c. 5 V d. 2.88 V Ans : d 74.If one of the diodes in a bridge full wave rectifier opens, the output is a. 0V b. one-fourth the amplitude of the input voltage c. a half wave rectified voltage d. a 120Hz voltage Ans : d Ans : c Sinhgad College of Engineering Page 9 Basic Electronics Engineering 75.If you are checking a 60 Hz full wave bridge rectifier and observe that the output has 60Hz ripple a. the circuit is working properly b. there is an open diode c. the transformer secondary is shorted d. the filter capacitor is leaky Ans : b 76.With a half wave rectified voltage across the load resistor, load current flows for what part of a cycle? a. 0 degree b. 90 degree c. 180 degree d. 360 degree Ans : c 77.Suppose line voltage may be as low as 105 V rms or as high as 125 V rms in a half wave rectifier. With a 5 : 1 step down transformer, the minimum peak load voltage is closest to a. 21 V b. 25 V c. 29.7 V d. 35.4 V Ans : c 78.The voltage out of a bridge rectifier is a a. half wave signal b. full wave signal c. bridge rectified signal d. sine wave Ans : b 79.What is the peak load voltage in a full wave rectifier if the secondary voltage is 20 V rms? a. 0 V b. 0.7 V Sinhgad College of Engineering Multiple Choice Questions c. 14.1 V d. 28.3 V Ans : c 80.We want a peak load voltage of 40 V out of a bridge rectifier. What is the approximate rms value of secondary voltage? a. 0 V b. 14.4 V c. 28.3 V d. 56.6 V Ans : c 81.With a full wave rectified voltage across a load resistor, load current flows for what part of a cycle? a. 0 degree b. 90 degree c. 180 degree d. 360 degree Ans : d 82.With the same secondary voltage and filter, which of the following has the most ripple? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. impossible to say Ans : a 83.With the same secondary voltage and filter which of the following produces the least load voltage? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. impossible to say Page 10 Basic Electronics Engineering Multiple Choice Questions Ans : a Ans : a 84.If the filtered load current is 10 mA, which of the following has a diode current of 10 mA? a. half wave rectifier b. full wave rectifier c. bridge rectifier d. All above 89.Ripple factor of full wave rectifier is a. 0.122 b. 0.4 c. 0.48 d. 0.05 Ans : d Ans : c 85.The diodes in a bridge rectifier each have a maximum dc current rating of 2 A. this means the dc load current can have maximum value of a. 1 A b. 2 A c. 4 A d. 8 A 90.Efficiency of bridge rectifier is a. 81.2 % b. 40.6 % c. 45.6 % d. 82.1 % Ans : b 91.Ripple factor of bridge rectifier is a. 0.122 b. 0.4 c. 0.48 d. 0.05 86.Efficiency of half wave rectifier is a. 81.2 % b. 40.6 % c. 45.6 % d. 82.1 % Ans : b 87.Ripple factor of half wave rectifier is a. 2.122 b. 1.112 c. 1.211 d. 2.11 Ans : a Ans : c 92.In a full-wave rectifier, the current in each of the diodes flows for a. the complete cycle of the input signal b. half cycle of the input signal c. less than half cycle of the input signal d. zero time Ans : b Ans : c 88.Efficiency of full wave rectifier is a. 81.2 % b. 40.6 % c. 45.6 % d. 82.1 % Sinhgad College of Engineering 93.To minimize the ripple content in the circuit a. Diode circuit is used b. filter circuit is used c. bridge circuit is used d. none of the above Page 11 Basic Electronics Engineering Ans: b 94.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz? a. 60Hz b. 50Hz c. 120Hz d. this is impossible to determine Ans: c 95.The ideal dc output voltage of a capacitor input filter is equal to a. the peak value of the rectified voltage b. the average value of the rectified voltage c. the rms value of the rectified voltage d. none of the above Ans: a 96.A certain power supply filter produces an output with a ripple of 100 mV peak-to-peak and dc value of 20V. the ripple factor is a. 0.05 b. 0.005 c. 0.0005 d. 0.02 Multiple Choice Questions c. changes in load resistance and input voltage d. changes in zener current and load current Ans: d 99.If you are checking a 60 Hz full wave bridge rectifier and observe that the output has 60Hz ripple a. the circuit is working properly b. there is an open diode c. the transformer secondary is shorted d. the filter capacitor is leaky Ans: b 100. Types of filter are a. Capacitor input filter b. choke input filter c. resister input filter d. both A and B Ans: d 101. Due to large........, capacitor holds its entire charge. a. charging current b. time constant c. discharging current d. none of these Ans: b Ans: b 97.Line regulation is determined by a. load current b. zener current and load current c. changes in load resistance and output voltage d. changes in output voltage and input voltage Ans: d 98.Load regulation is determined by a. changes in load current and input voltage b. changes in load current and output voltage Sinhgad College of Engineering 102. Due to the ........time constant the capacitor holds its entire charge. a. zero b. negative c. very large d. unity Ans: c Page 12 Basic Electronics Engineering 103. For a HWR using RL=1500Ω, a capacitor filter is used with C=100µF then its ripple factor at 50HZ is....... a. 0.115 b. 0.577 c. 0.0288 d. 0.0385 Ans: d 104. For a FWR using RL=1000Ω, a capacitor filter is used with C=100µF then its ripple factor at 50HZ is....... a. 0.115 b. 0.577 c. 0.0288 d. 0.0385 Ans: c 105. In a HWR using capacitor filter of 50µF, Esm=42V and Idc=2 mA then its output d.c. voltage is...........V. a. 41.6 b. 42 c. 41.8 d. 55 Ans: a 106. In a FWR using capacitor filter of 50µF, Esm=42V and Idc=2 mA then its output d.c. voltage is...........V. a. 41.6 b. 42 c. 41.8 d. 55 Ans: c 107. As load resistance increases, the ripple factor of capcitor filter........... Sinhgad College of Engineering Multiple Choice Questions a. decreases b. increases c. remains constant d. none of these Ans: a 108. As the value of filter capacitor decreases, the ripple factor of capacitor filter........ a. decreases b. increases c. both a and b d. None of the above Ans: b 109. As the value of filter capacitor increases, the ripple factor of capacitor filter........ a. decreases b. increases c. both a and b d. None of the above Ans: a 110. As load resistance decreases, the ripple factor of capcitor filter........... a. decreases b. increases c. remains constant d. none of these Ans: b 111. As the value of filter increases.............. a. ripple factor increases b. initial surge current increases c. regulation increases d. all of these capacitor Ans:b Page 13 Basic Electronics Engineering 111. A capacitor of 470µF is used as filter for a FWR using maximum input voltage of 30V at 50 HZ. Then its output d.c. voltage is.....V if RL=100Ω. a. 35.55 b. 25.94 c. 27.96 d. 39.54 Multiple Choice Questions 115. The output d.c. voltage of a rectifier using a capacitor filter is 20V while its ripple factor is 2.88% then the r.m.s. value of ripple voltage is .. a. 0.288 b. 0.576 c. 0.347 d. 0.144 Ans: b Ans: c 112. A capacitor of 470µF is used as filter for a HWR using maximum input voltage of 30V at 50 HZ. Then its output d.c. voltage is.....V if RL=100Ω. a. 35.55 b. 25.94 c. 27.96 d. 39.54 116. If the rms value of ripple voltage is 0.2886V then peak to peak value of the ripple voltage is.........V assuming triangular nature of the ripple voltage. a. 0.204 b. 0.408 c. 0.5 d. 1 Ans: b Ans: b 113. A capacitor of 100µF is used as a filter for HWR supplying a load of RL=1000Ω then ripple factor is............ a. 0.002 b. 0.048 c. 0.0355 d. 0.0577 Ans: d 114. A capacitor of 470µF is used as a filter for bridge rectifier supplying a load of RL=1000Ω then ripple factor is............ a. 0.0288 b. 0.00614 c. 0.00355 d. 0.00577 117. In a filter circuit ........is always connected in series with the load. a. resistor b. inductor c. capacitor d. none of these Ans: b 118. Ripple factor ..............as the value of filter capacitor increases. a. remains same b. decreases c. increases d. none of these Ans: b Ans: b Sinhgad College of Engineering Page 14 Basic Electronics Engineering 119. The ripple factor for the capacitor filter is ............for FWR. a. 1/4√3fCRL b. 1/2fCRL c. 1/2πfCRL d. 1/πfCRL Ans: a 120. The ripple factor for the capacitor filter is ............for HWR. a. 1/4√3fCRL b. 1/2fCRL c. 1/2πfCRL d. 1/2√3fCRL Ans: d 121.The ripple factor for the capacitor filter is ............for Bridge FWR rectifier. a. 1/4√3fCRL b. 1/2fCRL c. 1/2πfCRL d. 1/2√3fCRL Ans: a 122. If looking from the rectifier side, the first element in the filter is a capacitor then it is called ........filter. a. Choke input b. capacitor c. π d. RC Ans: b 123. In a filter circuit ........is always connected in parallel with the load. a. resistor b. inductor c. capacitor Sinhgad College of Engineering Multiple Choice Questions d. none of these Ans: c 124. For FWR with capacitor filter, diode conducts for .......half cycle. a. less than b. more than c. equal to d. none of these Ans: a 125. The circuits used to remove unwanted portion of waveform without disturbing the remaining part are called.......... a. clampers b. clippers c. chopper d. integrator Ans: b 126. The clipper circuits are also called as ......... a. filters b. rectifiers c. limiters d. integrators Ans: c 127. In a clamper,.........is necessary in addition to a diode. a. transistor b. inductor c. capacitor d. none of these Ans: c 128.One of the application of zener diode is a. Clipper Page 15 Basic Electronics Engineering b. Clamper c. Voltage regulator d. all above Multiple Choice Questions c. Clipper d. Regulator Ans: b Ans: c 129. Clipper circuit are used for a. rectification b. Removing part of wave form c. Shiftingof DC level d. All 134.Series Negative clipper will clip off a. positive half cycle of i/p b. both half cycle of i/p c. negative half cycle of i/p d. none Ans: c Ans: b 130.Clamper circuit are used for a. rectification b. Removing part of wave form c. Shifting of DC level d. All 135. Negative clampers add a DC voltage to the AC input a. Positive b. negative c. zero d. both Ans: c Ans: b 131. Positive clampers adds...............DC voltage to the AC input a. Positive b. negative c. zero d. both 136. Series Positive clipper will clip off a. positive half cycle of i/p b. both half cycle of i/p c. negative half cycle of i/p d. none Ans: a Ans: a 132.The basic circuit of half wave doubler is a. Clamper b. Rectifier c. Clipper d. Regulator 137. In a series clipper, ............is connected inn series with load. a. Diode b. inductor c. transistor d. capacitor Ans: a Ans: a 133. The basic circuit of full wave doubler is a. Clamper b. Rectifier 138. In a.......... Clipper, a diode is connected in parallel with the load. a. series Sinhgad College of Engineering Page 16 Basic Electronics Engineering b. combinational c. parallel d. two way Ans: c 139. A negative clipper clips off...........portion of the input waveform. a. positive b. negative c. peak d. none of these Ans: b 140. A positive clipper clips off...........portion of the input waveform. a. positive b. negative c. peak d. none of these Ans: a 141. In a series clipper, for a clipping region, the diode must be in ...........condition. a. forward biased b. reverse biased c. none of these d. a and b Ans: b 142. In a series clipper, for a transmitting region, the diode must be in ...........condition. a. forward biased b. reverse biased c. none of these d. a and b Ans: a Sinhgad College of Engineering Multiple Choice Questions 143. In a series clipper, the slope of the transfer characteristics in transmitting region is............ a. zero b. unity c. infinite d. negative Ans: b 144. In a series clipper, the slope of the transfer characteristics in clipping region is............ a. zero b. unity c. infinite d. negative Ans: a 145. In a parallel clipper, Vo = Vin can be obtained in transmitting region by making............ a. R1>>RL b. R1=RL c. R1<<RL d. none of these Ans: c 146. In a combinational clipper, when both the diodes are off, it produces ...........action. a. clipping b. transmitting c. exponential d. none of these Ans: b 147. In a ............clamper, the capacitor gets charged during first quarter of the negative cycle of the input. a. positive b. negative Page 17 Basic Electronics Engineering c. combinational d. two way Ans: a 148. In a ............clamper, the capacitor gets charged during first quarter of the positive cycle of the input. a. positive b. negative c. combinational d. two way Ans: b 149. Once charged to peak value, a capacitor acts as .........in a clamper. a. filter b. multiplier c. battery d. rectifier Ans: c 150. In a clamper, the analysis must start considering that part of the input which ......... a. reverse biases the diode b. forward biases the diode c. discharges the capacitor d. none of these Ans: b 151. ...........is assumed in the clamper. a. capacitor charges exponentially and discharges instantly. b. capacitor charges instantly and discharges instantly. c. capacitor charges instantly and does not discharge at all. d. capacitor charges exponentially and discharges exponentially. Sinhgad College of Engineering Multiple Choice Questions Ans: c 152. ---------- is action used in multiplier. a. clipping b. Clamping c. rectifying d. slicing Ans: b 153.In a half wave voltage doubler, the capacitor charges in ------------a. alternate half cycle b. each half cycle c. first positive half cycle d. none of these Ans: a 154.The voltage regulation of multipliers is a. very good b. poor c. zero d. none of these Ans: b 155. --------- is not required in Voltage multipliers a. Center tap transformer b. Diode c. Capacitor d. None of these Ans: a 156.PIV of diode in Full wave doubler is a. Vm b. 2Vm c. 3Vm d. none Page 18 Basic Electronics Engineering Multiple Choice Questions Ans: b Ans: a 157.The basic circuit of half wave doubler is a. Clamper b. Rectifier c. Clipper d. Regulator 162.A 12 V zener diode has a 1W power rating. What is the maximum rated zener current? a. 120 mA b. 83.3 mA c. 46.1 mA d. 1A Ans: a Ans: b 158.The zener diode is generally operated in a. Forward breakdown region b. reverse breakdown region c. middle breakdown region d. all above Ans: b 159.One of the application of zener diode is a. Clipper b. Clamper c. Voltage regulator d. all above Ans: c 160.A zener diode……… a. has a high forward-voltage rating b. has a sharp breakdown at low reverse voltage c. is useful as an amplifier d. has a negative resistance Ans: b 161.The doping level in a zener diode is ….. that of a semiconductor diode. a. more than b. less than c. the same as d. none of the above Sinhgad College of Engineering 163.A general purpose diode is more likely to suffer avalanche breakdown rather than zener breakdown because a. its leakage current is small b. it has weak covalent bonds c. it is lightly doped d. it has low reverse resistance Ans: c 164.Once a zener diode goes into breakdown, its ……….doesn’t change much a. voltage b. current c. dynamic impedance d. capacitance Ans: a 165.Load regulation is determined by a. changes in load current and input voltage b. changes in load current and output voltage c. changes in load resistance and input voltage d. changes in zener current and load current Ans: b 166.For a certain 12 V zener diode, a 10 mA change in zener current produces a 0.1 V change in zener voltage. The Zener impedance for this current range is Page 19 Basic Electronics Engineering a. 1 W b. 100 W c. 10 W d. 0.1 W Ans: c 167.If the load resistance increases in a zener regulator, the zener current a. decreases b. stays the same c. increases d. equals the source voltage divided by the series resistance Ans: c 168.Practically zener diodes are operated in a. Forward breakdown region b. reverse breakdown region c. middle breakdown d. all above Ans: b 169.A zener diode has………….. a. one pn-junction b. two pn-junctions c. three pn-junctions d. none of the above Ans: a 170.A zener diode is operated in the following mode as a voltage stabilizer a. reverse bias b. forward bias c. beyond the breakdown region d. reverse bias around the knee of breakdown region Ans: d Sinhgad College of Engineering Multiple Choice Questions 171.For a certain 12 V zener diode, a 10 mA change in zener current produces a 0.1 V change in zener voltage. The Zener impedance for this current range is a. 1 ohm b. 100 ohm c. 10 ohm d. 0.1 ohm Ans: b 172.An optical diode which emits light when forward biased is a. LED b. LCD c. TFT d. None of above Ans: a 173.The color of emitted light decided by a. Semiconductor material b. Wavelength c. type d. all above Ans: a 174.The approximate voltage drop across a forward- biased LED is a. 0.3 V b. 0.7 V c. 5.6 V d. 2.0 V Ans: d 175.LEDs have replaced incandescent lamps in many applications because they have……. a. a lower operating voltage b. a longer life c. . faster on-off switching Page 20 Basic Electronics Engineering d. all the advantages as a, b,c,d Ans: d 176. A display using seven LEDs is called a. bar graph display b. seven segment display c. matrix display d. none of these Multiple Choice Questions 180.As compared to a silicon rectifier diode, an LED has a a. lower forward voltage and lower breakdown voltage b. lower forward voltage and higher breakdown voltage c. higher forward voltage and lower breakdown voltage d. higher forward voltage and higher breakdown voltage Ans: b Ans: c 177. Which of the following group of letters can be displayed on seven segment display? a. A,C b. b,d c. F,C d. all of these 181.Types of seven segment display are a. Common anode type b. common gate type c. common cathode type d. both A and B Ans: d Ans: d 178.The internal resistance of a photodiode a. increases with light intensity when reverse biased b. decreases with light intensity when reverse biased c. increases with light intensity when forward biased d. decreases with light intensity when forward biased 182.An infrared LED is optically coupled to a photodiode. When the LED is turned off, the reading on an ammeter in series with the reverse biased photodiode will a. not change b. decrease c. increase d. fluctuate Ans: b Ans:b 179.To display the digit 0 in a seven segment indicator a. C must be off b. G must be off c. F must be on d. all segments must be lighted Ans: b Sinhgad College of Engineering 183. The semiconductor material used for LED is a. Gallium Arsenide b. gallium bromide c. Silicon d. Germanium Ans: a 184. The graph of ____ is called spectral response of LED. Page 21 Basic Electronics Engineering a. Forward Voltage Vs wavelength b. Current Vs forward voltage c. current Vs forward voltage d. light output Vs wavelength Multiple Choice Questions b. forward biased c. parallel with load d. none of these Ans: a Ans: d 185. The LED emits light when_______biased. a. reverse b. unbiased c. forward d. none of these 190. _______ is always operated in reverse biased condition. a. LED b. Photodiode c. Transistor d. Rectifier Ans: d Ans: b 186. The LED works on the principle of a. fluroscence b. hall effect c. electroluminescene d. none of these 191. The current in photodiode increases as the light intensity. a. remains same b. decreases c. increases d. none of these Ans: c Ans: c 187. GaAsP LEDs are used to produce __________ color light. a. red b. green c. orange d. white 192. The dark current in photodiode is due to ________ charge carriers. a. majority b. minority c. both the d. none of these Ans: a 188. The ______controls the brightness of LED. a. Forward voltage b. Forward current c. Materal used d. none of these Ans: b 193. The photodiode is _______ device. a. photoemitter b. photorejector c. photodetector d. none of these Ans: b Ans: d 189. A photodiode operates in __ condition. a. reverse biased 194. The luminous efficiency of LEDs is _____. a. high Sinhgad College of Engineering Page 22 Basic Electronics Engineering Multiple Choice Questions b. low c. zero d. none of these b. reverse current c. intensity of light d. none of these Ans: b Ans: c 195. The luminous efficiency of LEDs is measured in ______ . a. lumens/watt b. watts/lumen c. lumens/degree C d. lumens/ampere 200. The intensity of light is measured in ______ . a. Lm/A b. Lm/W c. Lm/w2 d. Lm/m2 Ans: a Ans: d 196. _______ is used in optocouplers. a. Zener b. LED c. SCR d. Transformer 201. The photodiode characteristics lies in _____ quadrant. a. first b. second c. third d. fourth Ans: b Ans: c 197. The photodiode current under no light is called _______ current. a. forward b. maximum c. dark d. none of these 202. The current is photodiode is due to ______ carriers. a. majority b. minority c. both d. none of these Ans: c 198. The dark current of photodiode is always a. large b. very small c. zero d. infinite Ans: b 203. The LED is _______ device. a. photoemitter b. photorejector c. photodetector d. none of these Ans: b Ans: a 199. Photo current is directly proportional to __ a. forward current 204. A photodiode converts _____ . a. light energy into chemical energy Sinhgad College of Engineering Page 23 Basic Electronics Engineering Multiple Choice Questions b. chemical energy into electrical energy c. light energy into electrical energy d. electrical energy into light energy Ans: c 205. A LED converts ___ . a. light energy into chemical energy b. chemical energy into electrical energy c. light energy into electrical energy d. electrical energy into light energy Ans: d UNIT II Bipolar Junction Transistor (BJT Circuits) Structure, operation and Biasing 1. Transistor is a _________ terminal device. a. Two b. Three c. Four d. both (a. and (b. a. b. c. d. transfer resistor trans resistor tri resistor none of the above Ans: a Ans: b 2. The three terminals of transistor are: a. Gate, collector and emitter b. Collector, base and source c. Base, collector and emitter d. Base, gate and collector 4. BJT is a ______ device. a. unipolar b. bipolar c. multipolar d. both b and c Ans: b Ans: c 3. The transistor means ______ . 5. In Unipolar transistor, the current conduction is due to _________ . Sinhgad College of Engineering Page 24 Basic Electronics Engineering a. minority carriers b. majority carriers c. both minority and majority carriers d. all of the above Ans: b Multiple Choice Questions c. doping d. mixing Ans: c 6. In bipolar transistor, the current is due to a. holes b. electrons c. both holes and electrons d. all of the above 11. Base of the transistor is always ___ and ____ doped. a. thick, lightly b. thin, lightly c. thin, heavily d. none of the above Ans: c Ans: b 7. BJT IS __________ controlled device. a. field b. voltage c. resistor d. current 12. The collector of a transistor is ______ doped. a. heavily b. moderately c. lightly d. none of the above Ans: d Ans: a 8. The types of bipolar junction transistors are a. ppn,npn b. pnp, npn c. npp, ppn d. nnp, pnp Ans: b 9. The middle region of a transistor is called __ a. base b. collector c. emitter d. none of the above Ans: a 10. The process by which impurities are added to a pure semiconductor is a. Diffusing b. drift Sinhgad College of Engineering 13. In transistors the collector region is larger than the emitter region for ______. a. better heat dissipation b. higher value of ß c. better amplification d. all of the above Ans: a 14. Doping concentration is highest in ________ of a BJT. a. emitter region b. collector region c. base region d. all of the above Ans: a Page 25 Basic Electronics Engineering 15. The ______ region has highest thickness than all other regions in a BJT. a. base b. collector c. emitter d. all of the above Ans: b 16. The arrow in the transistor symbol indicates the direction of ____. a. conventional emitter current b. electron current in emitter c. supply current d. both a and b Ans: a 17. The arrow in the transistor symbol indicates _______ terminal. a. base b. collector c. emitter d. none of the above Ans: c 18. Transistor has _______ pn junctions. a. one b. two c. three d. none of the above Ans: b 19. The depletion region at emitter junction in an unbiased transistor extends more into the _____ region. a. collector b. base c. emitter d. none of the above Sinhgad College of Engineering Multiple Choice Questions Ans: b 20. The depletion region at collector junction in an unbiased transistor extends more into the base region because it is _______ doped. a. heavily b. moderately c. lightly d. none of the above Ans: c 21. Barrier voltage is _____ on the N side. a. positive b. negative c. zero d. none of the above Ans: a 22. _______ of electrons and holes in the base region consists the base current. a. Ionization b. Recombinations c. Thermal agitation d. None of the above Ans: b 23. ________ constitute the dominant current in a npn transistor. a. Holes b. Electrons c. Both holes and electrons d. none of the above Ans: c 24. The current gain of a transistor is defined as the ratio of the collector current to the _____. a. base current Page 26 Basic Electronics Engineering Multiple Choice Questions b. emitter current c. supply current d. collector current d. largest for collector region Ans: a 29. When NPN transistor is used as amplifier a. electrons move from base to emitter b. electrons move from emitter to base c. electrons move from collector to base d. holes move from base to emitter 25. A transistor __________. a. is similar to a relay in that it uses a small amount of current to control a larger amount of current flow. b. has three connections called the base, emitter and collector c. is like a switch in that it is used to turn a circuit on and off d. all of the above Ans: d 26. The graph of current gain versus collector current indicates that the current gain _______. a. is constant b. varies slightly c. varies significantly d. equals the collector current divided by the base current Ans: b 27. _______ is the highest current in any bipolar transistor. a. IB b. IC c. IE d. none of the above Ans: c 28. The concentration of impurities in a transistor: a. equal for emitter, base and collector b. least for emitter region c. largest for emitter region Sinhgad College of Engineering Ans: c Ans: b 30. The base is made thin and lightly doped because a. about 95% of the charge carriers may cross b. about 100% of the charge carriers may cross c. the transistors can be saved from large currents d. none of these Ans: a 31. Base to emitter voltage in forward biased transistor decreases with the increase of temperature at the following rate: a. 2.5 mV/degree C b. 25 mV/degree C c. 0.25 mV/degree C d. 0.6 mV/degree C Ans: a 32. No. of depletion layers in a transistor are __ a. two b. three c. four d. none of the above Ans: a 33. The emitter of a transistor is _____ doped. a. moderately Page 27 Basic Electronics Engineering Multiple Choice Questions b. heavily c. lightly c. less than 1 d. 0 Ans: b 34. The input impedance of a transistor is ____ as compared to MOSFET. a. low b. high c. very high d. none of above Ans: a 39. Transistor biasing condition. a. ac b. dc c. both ac and dc d. none of the above Ans: a Ans: b 35. In an NPN transistor, ______ are the minority carrier. a. electron b. holes c. donor ions d. acceptor ions 40. Transistor biasing is generally provided by a ________. a. biasing circuit b. biasing battery c. diode d. none of the above Ans: b Ans: a 36. In a transistor _____. a. IB=IC+IB b. IC=IE+IB c. IE=IC+IB d. IE=IC-IB 41. The point of intersection of DC and AC load lines represents _______. a. current point b. operating point c. voltage gain d. none of the above represents ____ Ans: c Ans: b 37. The value of alpha of a transistor is ________. a. 0 b. 1 c. more than 1 d. less than 1 Ans: d 38. The value of ß of a transistor is ________. a. between 20 and 500 b. 1 Sinhgad College of Engineering 42. The phase difference between the input and output voltage in a common base arrangement is ________. a. 90 b. 180 c. 0 d. none of the above Ans: c Page 28 Basic Electronics Engineering 43. The phase difference between the input and output voltage in a common emitter arrangement is ________. a. 0 b. 180 c. 90 d. 270 Ans: b 44. The phase difference between the input and output voltage in a common collector arrangement is ________. a. 0 b. 90 c. 180 d. 270 Ans: a 45. The early effect in a bipolar transistor is caused by: a. Large collector-base reverse bias b. base width modulation c. large emitter-base forward bias d. increase in junction temperature Ans: b 46. The _____ current of a transistor is neither the largest nor the smallest. a. Base b. Collector c. emitter d. none of the above Ans: b 47. Which of the following currents are nearly equal to each other? a. IB and IC b. IE and IC Sinhgad College of Engineering Multiple Choice Questions c. IB and IE d. Ib,IC and IE Ans: b 48. For a properly biased transistor, let IC=10mA and Ie=10.2mA. What is the level of IB? a. 0.2A b. 200mA c. 200µA d. 20.2mA Ans: c 49. Holes flow constitutes the dominant current in a _______ transistor. a. npn b. pnp c. a and b d. none of the above Ans: b 50. When the collector current increases, what does the current gain do? a. decreases b. stays the same c. increases d. any of the above Ans: c 51. When the base resistor increases, the collector voltage will probably ________. a. decrease b. stays the same c. increase d. do all of the above Ans: c Page 29 Basic Electronics Engineering 52. If the base resistor is very small, the transistor will operate in the _______. a. cut off region b. active region c. saturation region d. all of the above Ans: c 53. Ignoring the bulk resistance of the collector diode, the collector-emitter saturation voltage is _____. a. 0V b. a few tenths of a volt c. 1V d. supply voltage Ans: a 54. For common base transistor teh numerical value is least for _______. a. voltage gain b. power gain c. resistance gain d. current gain Multiple Choice Questions b. reverse c. zero d. none of the above Ans: a 57. In which region are both the collector-base and base-emitter junctions forward biased for BJT? a. active b. cut-off c. saturation d. all of the above Ans: c 58. For the BJT to operate in the saturation region, the base-emitter juntion must be ______ biased and the base-collector junction must be ________. a. forward, forward b. forward, reverse c. reverse, reverse d. reverse, forward Ans: a Ans: d 55. For operating in the active region, the emitter junction should be _____ biased and collector junction should be ____ biased in BJT. a. forward, forward b. reverse, reverse c. forward, reverse d. reverse, forward Ans: c 56. The emitter junction is ____ biased for operating BJT in saturation region. a. forward Sinhgad College of Engineering 59. At what region of operation is the baseemitter junction forward biased and the basecollector junction reverse biased for BJT? a. saturation b. linear or active c. cut-off d. none of the above Ans: b 60. The transistor acts as an amplifier in the ______ region. a. Cut off b. Active c. Saturation Page 30 Basic Electronics Engineering d. None of the above Ans: b 61. When there is no base current in a transistor switch, then output voltage from the transistor is ____. a. low b. high c. unchanged d. unknown Ans: b 62. A circuit with a fixed emitter current is called ______. a. base bias b. emitter bias c. transistor bias d. two supply bias Ans: b 63. The first step in analyzing emitter-based circuits is to find the ________. a. base current b. emitter current c. supply current d. collector current Ans: b 64. If the current gain is unknown in an emitterbiased circuit, you cannot calculate the _____. a. emitte voltage b. emitter current c. collector current d. base current Ans: d Sinhgad College of Engineering Multiple Choice Questions 65. If the emitter resistor is open, teh collector voltage is ________. a. low b. high c. unchanged d. unknown Ans: b 66. If the collector resistor is open, the collector voltage is _______. a. low b. high c. unchanged d. unknown Ans: a 67. When the current gain increases from 50 to 300 in an emitter-biased circuit, the collector current ________. a. remains almost the same b. decreases by a factor of 6 c. increases by a factor of 6 d. is zero Ans: a 68. If the emitter resistance increases, the collector voltage ______. a. decreases b. stays the same c. increases d. breaks down the transistor Ans: c 69. When using a DMM (Digital multimeter) to test a transistor, an approximate reading of 0.7V will be found with how many polarity connections? a. One Page 31 Basic Electronics Engineering b. Two c. Three d. None Multiple Choice Questions a. b. c. d. high, high low, low low, high high, low Ans: b Ans: c 70. What DMM polarity connection is needed on an npn transistor's base to get a 0.7V reading? a. positive b. negative c. either positive or negative d. unknown 74. We can not operate the transistor in ______ region for the switching applications. a. cut-off b. active c. saturation d. all of the above Ans: a Ans: b 71. When testing an npn transistor using an ohmmeter, the collector-emitter resistance will be low when ________. a. The collector is positive in respect to the emitter b. The emitterr is positive in respect to the collector c. The transistor is normal d. The transistor is defective Ans: d 72. The transistor is operated as a open switch in ______ region. a. Cut off b. Active c. Saturation d. None of the above Ans: a 73. The transistor may be used as a switch so that when it is in the saturated state its on resistance is very _______ and in the cut-off state its off resistance is very ________. Sinhgad College of Engineering 75. The transistor is operated as a close switch in ______ region. a. cut-off b. active c. saturation d. all of the above Ans: c 76. Transistor is used as a switch in ______. a. an amplifier b. logic gate c. linear DC power supply d. none of the above Ans: b 77. Which of the following configurations can a transistor set up? a. common base b. common emitter c. common collector d. all of the above Ans: d Page 32 Basic Electronics Engineering 78. In CB configuration a reverse biased collector junction IC=_____ when the emitter is left open. a. 0 b. IE c. ICBO d. none of the above Multiple Choice Questions 83. The alpha dc is always ________ . a. unity b. less than unity c. greater than unity d. none of the above Ans: b Ans: c 79. ICBO flows from _______ to ________when emitter is open. a. collector, base b. base, collector c. collector, emitter d. none of the above Ans: a 80. The ______ carriers constitute current ICBO. a. both minority and majority b. minority c. majority d. none of the above 84. The collector current is 1.5mA. If the current gain is 50, the base current is ______. a. 3 µA b. 30 µA c. 150 µA d. 3 mA Ans: b 85. The base current is 50µA. If the current gain is 100, the collector current is closest in value to a. 50µA b. 500µA c. 2mA d. 5mA Ans: b Ans: d 81. ICBO current is _____. a. greater than IC b. increases with termperature c. less than ICO d. flows when base junction is forward biased 86. a=_______ . a. IB/IE b. IC/IE c. IC/IB d. none of the above Ans: b Ans: b 82. With rise in temperature ICBO ____. a. increases linearly b. doubles at every 10 degree celcius c. decreases linearly d. none of the above Ans: b Sinhgad College of Engineering 87. smaller the thickness of base, _______ is the value of alpha dc. a. smaller b. larger c. constant d. none of the above Page 33 Basic Electronics Engineering Multiple Choice Questions Ans: b 88. The a is the current gain of ___ configuration. a. CB b. CC c. CE Ans: a 89. In CB configuration input resistance is __ a. change in VEB/change in IE b. change in VCB/change in IE c. change in VCB/change in IC d. none of the above 93. In CB configuration dynamic output resistance is ______. a. low b. medium c. high d. none of the above Ans: c 94. alpha ac is the slope of ______ characteristic of transistor in CB configuration. a. input b. output c. transfer d. none of the above Ans: a Ans: c 90. The input resistance of CB configuration is measured at constant ______. a. IB b. IC c. VCB d. VCE 95. The transfer characteristics of CB show the relation between _________. a. IC and IE b. IC and IB c. IB and IE d. all of the above Ans: c Ans: a 91. The dynamic output resistance of transistor in CB configuration is ______ at constant IE. a. change in VEB/change in IE b. change in VEB/change in Ic c. change in VcB/change in Ic d. none of the above 96. Which terminal represents the control input of a bipolar transistor? a. emitter b. collector c. gate d. base Ans: c Ans: d 92. The dynamic output resistance of CB configuration is measured at constant _____ a. IB b. IC c. IE Ans: c Sinhgad College of Engineering 97. Which of the following expressions represents the DC current gain of a bipolar transistor? a. IC/IB b. dIC/dIB c. IC/VBE Page 34 Basic Electronics Engineering d. dIC/dVBE Ans: a 98. Output characteristics of common base configuration gives a. skin effect b. early effect c. reach through effect d. hall effect Ans: b 99. Early effect and base width modulation effect is ______. a. same b. different c. not related to each other d. both damages the transistor Ans: a 100. Input resistance for common base configuration is _______. a. 20 ohm b. 200 ohm c. 2 Kohm d. 2 Mohm Ans: a 101. Input resistance for common collector configuration is _______. a. 5 Kohm b. 50 Kohm c. 500 Kohm d. 5 Mohm Multiple Choice Questions a. b. c. d. 40 Kohm 400 Kohm 4 Mohm 40 Mohm Ans: a 103. Output resistance for common collector configuration is _______. a. 5 ohm b. 50 ohm c. 5 Kohm d. 500 Kohm Ans: b 104. Voltage gain in configuration is _________. a. always above unity b. unity c. less than unity d. not any above common base Ans: a 105. Voltage gain in CE configuration is ______ a. less than unity b. unity c. always above unity d. not any above Ans: c 106. Voltage gain in CC configuration is ____ a. less than unity b. unity c. always above unity d. not any above Ans: c Ans: a 102. Input resistance for common emitter configuration is _______. Sinhgad College of Engineering Page 35 Basic Electronics Engineering 107. Current amplification factor alpha dc is given by _____. a. IC/IE b. IE/IC c. IC/IB d. IE/IB Ans: a 108. Current amplification factor ßdc is given by _____. a. IC/IE b. IE/IC c. IC/IB d. IE/IB Ans: c 109. Current amplification factor gamm dc is given by _____. a. IC/IE b. IC/IB c. IE/IC d. none of the above Multiple Choice Questions Ans: b 112. Current gain in CB configuration is _______. a. unity b. less than unity c. greater than unity d. not any above Ans: b 113. Current gain in CE configuration is ______ a. 25 to few hundreds b. less than 10 c. 10 to 15 d. unity Ans: a 114. Current gain in CC configuration is _____ a. less than unity b. unity c. 25 to few hundreds d. less than 10 Ans: d Ans: c 110. For voltage amplifier function, suitable configuration is _______. a. CE configuration b. CC configuration c. CB configuration d. none of the above 115. Input resistance for Common Emitter Configuration is _______. a. 100 ohm b. 1Kohm c. 1 Mohm d. 100Kohm Ans: c 111. Output resistance for Common Base Configuration is _______. a. 1 Kohm b. 1 Mohm c. 10 Kohm d. 100 Mohm Sinhgad College of Engineering Ans: b 116. In bipolar transistor, the current flows due to _____. a. minority carriers b. majority carriers c. both, majority and minority carriers d. none of the above Page 36 Basic Electronics Engineering Ans: c Multiple Choice Questions 117. Transistor device is used in the application such as ________. a. switch b. amplifier c. oscillator d. above all 121. In a transistor as an amplifier, the reverse saturation current: a. Doubles for every degree C rise in temperature b. Doubles for every 10 degree C rise in temperature c. Decreases linearly with temperature d. Increase linearly with temperature Ans: d Ans: b 118. When transistor is unbiased then due to following, two diffrent depletion regions form in the transistor at two respective junction ______ a. only drift process b. drift and diffusion process c. only diffusion process d. diffusion and then drift process 122. The transfer characteristics of a CB configuration is a graph of _____. a. VCB, IC b. IE, IC c. VEB, IE d. none of the above Ans: b Ans: c 119. In common base configuration, the width of depletion region also increases, which reduces the electrical base width, this effect is known as ____. a. hall effect b. skin effect c. early effect d. piezo-electric effect Ans: c 120. Which of the following expressions represents the transconductance of a bipolar transistor? a. dIC/dIB b. IC/IB c. dIC/dVBE d. IC/VBE Ans: c Sinhgad College of Engineering 123. In saturation region the collector current _____. a. is independent of IB b. is proportional to IB c. is equal to IB d. none of the above Ans: a 124. Shape of the transfer characteristics of CB configuration is ____. a. non-linear b. linear c. parabolic d. none of the above Ans: b 125. The reverse saturation current of CE configuration with base open is _______. a. ICEO Page 37 Basic Electronics Engineering b. ICBO c. ICO d. none of the above Ans: a 126. The voltage gain of an emitter follower is ______. a. 1 b. less than 1 c. greater than 1 d. none of the above Ans: b 127. In ________ configuration/s there is phase shift of 0 degree between input and output. a. CB b. CE c. CC d. CB and CC Multiple Choice Questions 130. For CE amplifier, ac input is applied to ___ a. emitter b. base c. collector d. none of the above Ans: b 131. For CE configuration, in the cut-off region, IC=______. a. ICBO b. ICEO c. 0 d. none of the above Ans: b 132. The ICEO in terms of ICBO is given by __ a. ICEO=(1+ß. ICBO b. ICEO=ß*ICBO+1 c. ICEO=ICBO/(1+ß. d. none of the above Ans: d 128. The output of ______ amplifier follows the input. Hence it is also called emitter follower. a. CB b. CE c. CC d. none of the above Ans: a 133. If R1 is the input resistance and R2 is the output resistance of the voltage gain A in the common emitter configuration is ________. a. alpha(R2/R1. b. ß(R2/R1. c. alpha d. ß Ans: c Ans: b 129. For an CC amplifier, the input is applied to _____ and the output is obtained at _______. a. emitter, base b. collector, base c. base, emitter d. none of the above 134. The current gain of CE configuration is ___ a. ßdc b. alpha dc c. gamma dc d. none of the above Ans: c Ans: a Sinhgad College of Engineering Page 38 Basic Electronics Engineering 135. ßdc=____. a. IB/IE b. IC/IE c. IC/IB d. none of the above Multiple Choice Questions 140. The input resistance of CE configuration is change in VBE/change in IB at constant _______ a. VCE b. VCB c. IC d. none of the above Ans: c Ans: a 136. The ratio of which two currents is represented by ß? a. IC and IE b. IC and IB c. IE and IB d. none of the above 141. The input resistance in CE configuration is ______ at constant VCE. a. change in VBE/change in IC b. change in VBE/change in IB c. change in VBE/change in IE d. None of the above Ans: b Ans: b 137. ß in terms of alpha is given by ______. a. ß=alpha/(1+alpha. b. ß=alpha/(1-alpha. c. ß=(1+alpha. /alpha d. none of the above Ans: b 138. ß in a transistor when IB=105µA, IC=2.05mA is ______. a. 11.5 b. 17.5 c. 13.5 d. 19.5 Ans: d 139. Determine the value of a when ß=100. a. 1.01 b. 101 c. 0.99 d. cannot be solved with the information provided Ans: c Sinhgad College of Engineering 142. The value of Ri in CE configuration is _____ that in CB configuration. a. lower than b. higher than c. same as d. none of the above Ans: b 143. The typical value of VBE(sat. in CE configuration for a Si transistor is _____. a. 0.7V b. 0.2V c. 0.9V d. none of the above Ans: a 144. Value of VBE(active) for a Ge transistor is _ a. 0.2 b. 0.6 c. 0.7 d. none of the above Page 39 Basic Electronics Engineering Multiple Choice Questions Ans: a d. greater than or equal to 145. The value of VBE(cut-off. for Si transistor is a. 0.7V b. 0V c. 0.3V d. none of the above Ans: c Ans: b 146. The output characteristics of a CE configuration is the graph of ________. a. VCE, VEC b. IC, VEC c. VCE, IC d. none of the above Ans: c 147. The value of dynamic output resistance in the CE configuration is ______ than in CB configuration. a. lower b. higher c. moderate d. none of the above Ans: a 148. Which of the following region is (are. part of the output characteristics of a transistor? a. Active b. cut-off c. saturation d. all of the above Ans: d 149. The saturation region is defined by VCE _____VCE(sat. . a. > b. < c. less than or equal to Sinhgad College of Engineering 150. In _______ region the collector current is proportional to the base current. a. saturation b. cut-off c. active d. none of the above Ans: c 151. The cut-off region is defined by IB _____ 0A. a. > b. < c. less than or equal to d. greater than or equal to Ans: c 152. When a transistor is operated with emitter diode forward biased and collector diode reverse biased, the collector current will be __ a. almost zero b. almost equal to the emitter current c. infinitely high d. many times more than the emitter current Ans: b 153. For a BJT, under the saturation condition _ a. IC=ß*IB b. IC > ßIB c. IC is independent of all other parameters d. IC < ßIB Ans: d 154. Which of the statement for the BaseEmitter and the collector-base junctions is/are true? Page 40 Basic Electronics Engineering a. IC is independent of VCE in the Active region. IC=0 and VCE=VCC in the cut-off region. IC=IC(sat) and VCE=0 in the saturation region. b. the B-E should be forward biased and the C-B should be reverse biased in the active region c. the base current IB controls the collector current IC in the active, cut-off and saturation regions d. all of the above Multiple Choice Questions Ans: b 159. The transfer characteristic configuration is _____. a. linear b. nonlinear c. parabolic d. none of the above in CE Ans: a Ans: b 155. A transistor is in saturation if a. IB>IC/ß b. IC/ß>/IB c. IC=ßIB d. none of the above 160. gamma=_____. a. IC/IB b. IE/IC c. IE/IB d. none of the above Ans: a Ans: c 156. A transistor is in active region if a. VCE > VCE(sat. b. VCE = VCE(sat. c. VCE < VCE(sat. d. none of the above 161. gamma =______. a. 1/(1+alpha) b. 1/(1-alpha) c. 1/(1+ß) d. none of the above Ans: a Ans: b 157. Typical value of VCE(sat. is _____. a. 0.7V b. 0.2V c. 0.6V d. none of the above 162. The ____ configuration is the most widely used. a. CB b. CE c. CC d. none of the above Ans: b Ans: b 158. The slope of the transfer characteristics in CE configuration is indicated by ______. a. ßdc b. ßac c. alphadc d. alphaac Sinhgad College of Engineering 163. The ____ configuration is used as an input stage. a. CB b. CE c. CC Page 41 Basic Electronics Engineering Multiple Choice Questions d. none of the above Ans: a 164. The input resistance of CC configuration is ____. a. low b. high c. 0 d. none of the above Ans: b 165. The value of input resistance in the CE configuration is _______ that in CB configuration. a. lower than b. higher than c. same as d. none of the above Ans: b 166. The current gain of common base npn transistor is 0.96. What is the current gain if it is used as common emitter amplifier? a. 16 b. 24 c. 20 d. 32 168. Iceo indicates a. collector Current b. emitter Current c. base current d. collector to Emitter current when base is open. Ans: d 169. In NPN transistor, the collector current is 24mA. If 80% of the electrons reach collector, the base current in mA is a. 36 b. 26 c. 16 d. 6 Ans: d 170. In a transistor circuit base current is increased by 50µA, the collector current increases by 1mA. The current gain of the transistor is a. 20 b. 40 c. 60 d. 80 Ans: a Ans: b 167. In a common emitter circuit, the collector current is 0.9 mA, base current is 100µA. The value of current gain and emitter current is ______. a. 49 and 2mA b. 9 and 1mA c. 0.9 and 0.1 mA d. none of these 171. A common emitter transistor amplifier has a current gain of 50. If the load resistance is 4Kohm and input resistance is 500 ohm, the voltage gain in amplifier is _____. a. 160 b. 200 c. 300 d. 400 Ans: d Ans: b Sinhgad College of Engineering Page 42 Basic Electronics Engineering 172. A common emitter amplifier is designed with npn transistor with alpha=0.99, the input impedance is 1 Kohm and load is 10Kohm. The voltage gain will be _______. a. 9.9 b. 99 c. 990 d. 9900 Ans: c 173. Transistor has lowest output impedance in ________ configuration. a. CB b. CE c. CC d. none of the above Ans: c 174. Current gain of transistor is lowest in ____________ Configuration. a. CB b. CE c. CC d. none of the above Ans: a 175. The output resistance of CC configuration is _____________ a. Very Low b. Low c. High d. None of these Ans: a 176. The ___________ of CC configuration is less than unity. a. Input resistance b. Current gain c. Voltage Gain Sinhgad College of Engineering Multiple Choice Questions d. None of the above Ans: c 177. Identify which configuration has following characteristics. Voltage gain is less than one, Input impedance high and output impedance very low. a. CB b. CE c. CC d. None of these Ans: c 178. _________ amplifier configuration provides both high current and voltage gain. a. CB b. CE c. CC d. None of these Ans: b 179. The ___________ configuration is used for impedance matching. a. CB b. CE c. CC d. None of these Ans: c 180. As compared to a CB amplifier, a CE amplifier has __________ a. Lower current amplification b. Higher current amplification c. Lower input resistance d. higher input resistance Ans: b Page 43 Basic Electronics Engineering Multiple Choice Questions 181. In ______________ configuration there is phase shift of 180 degree between input and output. a. CB b. CE c. CC d. None of these Ans: b 182. ________________ transistor configuration provides the highest input impedance. a. CB b. CE c. CC d. None of these Ans: c 183. The ___________ configuration is used as an output stage. a. CB b. CE c. CC d. None of these Ans: c 184. The Q point ______________. a. open point b. operating point c. DC point d. Breakdown point is also known as Sinhgad College of Engineering Ans: b 186. The position of Q point on the DC load line should be ______________. a. Stable b. unstable c. bistable d. tristable Ans: a 187. In CE configuration, co-ordinates of Q point are____________. a. Vce, Ib b. Vcb,Ic c. Vce,Ic d. Vce,Ie Ans: c 188.In CE configuration, the upper end of DC load line is called the ____________points and the lower end is the ____________ point. a. Q, base b. base, Q c. Saturation, Q d. cut-off, Q Ans: c Ans: b 185. The slope of a Dc represents_____________. a. Collector resistance b. reciprocal of DC load resistance c. reciprocal of AC load resistance d. None of the above load line 189. _____ has an important effect on shifting of the operating point. a. Voltage b. change in beta c. Current d. None of the above Ans: b Page 44 Basic Electronics Engineering 190. Which of the following factor affects the Q point stability? a. Temperature b. Bypass Capacitor c. Coupling Capacitor d. None of the above Ans: a 191. Three different Q points are shown on a load line. The upper Q point represents the ____. a. minimum current gain b. intermediate current gain c. maximum current gain d. cut-off point Ans: c 192. If a transistor operates at the middle of the load line, a decrease in the base resistance will move the Q point ____. a. down b. up c. no where d. off the load line Ans: b 193. If the base supply voltage increases, the Q point moves ________. a. down b. up c. no where d. off the load line Ans: b 194. When the Q point moves along the load line, VCE decreases when the collector current ________. a. decreases Sinhgad College of Engineering Multiple Choice Questions b. stays the same c. increases d. none of the above Ans: c 195. Suppose the base resistor is open. The Q point will be ______. a. in the middle of the load line b. at the upper end of the load line c. at the lower end of the load line d. off the load line Ans: c 196. If a transistor operates at the middle of the load line, a decrease in the current gain will move the Q point ________. a. down b. up c. no where d. off the load line Ans: a 197. If the base supply voltage is disconnected, the collector-emitter voltage will equal _______. a. 0V b. 6V c. 10.5V d. collector supply voltage Ans: d 198. If the base resistor has zero resistance, than transistor will probably be _______. a. saturated b. in cut-off c. destroyed d. none of the above Page 45 Basic Electronics Engineering Ans: c 199. If the collector resistor opens in a basebiased circuit, the load line will become ______. a. horizontal b. vertical c. useless d. flat Ans: a 200. If the emitter resistance decreases, the _____. a. Q point moves up b. collector current decreases c. Q point stays where it is d. current gain increases Ans: a 201. If the operating point of an npn transistor amplifier is selected in saturation region, it is likely to result in________________. a. thermal runway of transistor b. clipping of output in the positive half of the input signal c. need for high DC collector supply d. clipping of output in the negative half of the input signal Ans: b 202. The output voltage of an ampifier is 5V when an input voltage is 50mV. Its voltage gain is _______. a. 100 b. 250 c. 1000 d. none of the above Ans: a Sinhgad College of Engineering Multiple Choice Questions 203. The ideal voltage amplifier must have ______ input resistance. a. low b. high c. infinite d. none of the above Ans: c 204. The ideal value of Ro is ______. a. zero b. infinite c. very low d. none of the above Ans: a 205. Ideally the bandwidth of an amplififer should be _____. a. infinite b. low c. as high as possible d. none of the above Ans: a 206. The frequency of Vo of an amplifier is _______. a. less than that of Vin b. same as that of Vin c. greater than that of Vin d. none of the above Ans: b 207. Ideallly voltage gain of an ampllifier should be _______. a. zero b. high c. infinite d. none of the above Page 46 Basic Electronics Engineering Ans: c 208. In a common emitter amplifier output resistance is 5000 ohm and input resistance is 2000 ohm. If the peak value of signal voltage is 10mV and B=50, the peak value of voltage output is _____. a. 5 X 10^-6 V b. 2.5 X 10^-4 V c. 1.25V d. 125V Ans: c 209. The current gain of ______ amplifier is always less than unity. a. CB b. CE c. CC d. none of the above Ans: a 210. The voltage gain of _____ amplifier is always less than unity. a. CB b. CE c. CC d. none of the above Ans: c 211. The _______ amplifier can be used as buffer. a. CB b. CE c. CC d. none of the above Ans: c 212. MOSFET is a _____ controlled device. Sinhgad College of Engineering Multiple Choice Questions a. b. c. d. current voltage field all of the above Ans: b 213. It is the insulating layer of ______ in the MOSFET construction that accounts for the very desirable high input impedance of the device. a. SiO b. GaAs c. SiO2 d. HCI Ans: c 214. Which of the following applies to MOSFETs? a. No direct electrical connection between the gate terminal and the channel b. Desirable high input impedance c. Uses metal for the gate, drain and source connections d. All of the above Ans: d 215. How many terminals a MOSFET has? a. 2 b. 3 c. 4 d. 3 or 4 Ans: b 216. MOSFET is a ______ device. a. unipolar b. bipolar c. multipolar d. none of the above Page 47 Basic Electronics Engineering Multiple Choice Questions d. none of the above Ans: a 217. In MOSFET, the current flows due to ____ a. minority carriers b. majority carriers c. both, majority and minority carriers d. none of the above Ans: b 222. A MOSFET has a high input _____. a. current b. resistance c. inductance d. none of the above Ans: b Ans: b 218. Which of the following transistor(s) has(have) depletion and enhancement types? a. BJT b. JFET c. MOSFET d. none of the above 223. The packaging density of MOSFETs is ______ as compared to BJT. a. less b. high c. same d. none of the above Ans: d Ans: b 219. VLSI technology relies on _______. a. MOSFET b. BJT c. diode d. none 224. Because of insulated gate, MOSFET is also called _______. a. INFET b. IGFET c. IMOSFET d. IGMOSFET Ans: c Ans: b 220. For making n-channel enhancement MOSFET the substrate taken will be of type a. p b. n c. either p or n d. none of these 225. In a enhancement mode MOSFET, the channel is ______. a. always present b. always absent c. initially absent d. none of the above Ans: a Ans: c 221. The input resistance of MOSFET is ____ that of BJT. a. lower than b. higher than c. same as Sinhgad College of Engineering 226. For an n-channel EMOSFET VT is ____. a. negative b. zero c. positive Page 48 Basic Electronics Engineering Multiple Choice Questions d. none of the above Ans: b Ans: c 227. For an EMOSFET ID=0 for ________. a. VGS > VT b. VGS < VT c. VDS < VT d. none of the above 232. By connecting drain and gate terminals together EMOSFET can be used as ______. a. amplifier b. open switch c. resistor d. none of the above Ans: b Ans: c 228. In order to operate EMOSFET as an amplifier we have to operate it in ___ region. a. ohmic b. saturation c. cut-off d. none of the above 233. In n-channel EMOSFET, the conduction begins when _____. a. VGS=VT b. VDS=VP c. VDS=VDD d. none of the above Ans: b Ans: a 229. The EMOSFET acts as a ____ for VGS < VT. a. open switch b. closed switch c. resistor d. none of the above Ans: a 230. For an n-channel EMOSFET,ID _ for VGS=0. a. zero b. IDSS c. infinite d. none of the above Ans: a 231. In n-channel EMOSFET channel is ___ when VGS > VT. a. disappeared b. induced c. none of these d. all of the above Sinhgad College of Engineering 234. In enhancement type MOSFET, channel is present initially. a. The statement is false since channel is enhanced by applying gate voltage b. The statement is true c. No concept of channel is there d. All the above are false Ans: a 235. For an EMOSFET, the relation between ID and VGS is ______. a. ID=k(VGS-VT) b. ID=k2(VGS-VT) c. ID=k(VGS-VT)2 d. none of the above Ans: c 236. The drain characteristics of MOSFET is _______. Page 49 Basic Electronics Engineering a. b. c. d. VDS to ID VGS to ID both of the above none of the above Multiple Choice Questions Ans: c Ans: a 237. The transfer characteristics of MOSFET is _____. a. VDS to ID b. VGS to ID c. both of the above d. none of the above Ans: b 238. MOSFET is ______. a. multilayer oxide semiconductor field effect transistor b. most oxidized semiconductor field effect transistor c. metal oxide semiconductor field effect transistor d. none of the above Ans: c 239. MOSFETs are also called _________. a. IGFETs b. BJTs c. UJTs d. none of the above Ans: a 240. ______ and _____ are two basic types of MOSFETs. a. NPN and PNP b. IGFET and JFET c. DMOSFET and EMOSFET d. none of the above Sinhgad College of Engineering Page 50