智慧树知到《模拟电子技术基础（西安邮电大学版）》章节测试答案

智慧树知到模拟电子技术基础（西安邮电大学版）章节测试答案 智慧树知到模拟电子技术基础（西安邮电大学版）章节测试答案第一章1、Which of the following is not a commonly used semiconductor material? （ ）A:carbonB:leadC:siliconD:germanium答案: lead2、The characteristic of an ideal diode are those of a switch that can conduct current（ ） .A:in both directionsB:in one direction onlyC:in both directions but in only one direction at a timeD:depends on the circuit it is used in答案: in one direction only3、When a diode is doped with either a pentavalent or a trivalent impurity its resistance will （ ） .A:increaseB:decreaseC:make the resistance stable against variation due to temperature答案: decrease4、The piecewise linear model, equivalent circuit of the diode consists of （ ）.A:a junction capacitor, a battery, a small resistor, and the ideal diodeB:a battery, a small resistor, and the ideal diodeC:a battery and the ideal diodeD:the ideal diode答案: a battery, a small resistor, and the ideal diode5、When a p-n junction is reverse-biased, its junction resistance is （ ）.A:highB:lowC:determined by the components that are external to the deviceD:constantly changing答案: high第二章1、What is the value of the voltage dropped across forward-biased silicon diodes that are connected in parallel with each other? （ ）.A:11.3 VB:35 VC:7 VD:4 V答案: 7 V2、The resistor voltage and resistor current in this circuit are （ ）.image.pngA:10 V, 5 mAB:11 V, 2 mAC:11 V, 11 mAD:2 V, 11 mA答案: 11 V, 11 mA3、Which of the following circuits is used to eliminate a portion of a signal? （ ）.A:ClipperB:DamperC:Voltage multiplierD:Voltage divider答案: Clipper4、The circuit shown here is a （ ）. image.pngA:series clipperB:parallel clipperC:series clamperD:shunt clamper答案: parallel clipper5、The Zener diode must be operated such that （ ）.A:image.pngB:image.png is less than the specified image.pngC:the applied voltage is greater than image.pngD:All of these答案: All of these第三章1、In the active region, the base-emitter junction （ ）.A:and the base-collector junctions are both forward-biasedB:and the base-collector junctions are both reverse-biasedC:is forward-biased while the base-collector junction is reversed-biasedD:is reverse-biased while the base-collector junction is forward-biased答案:C2、A BJT has measured dc current values of image.png = 0.1 mA and image.png= 8.0 mA. When IB is varied by 100 A, IC changes by 10 mA. What is the value of the ac for this device?（ ）.A:80B:10C:100D:800答案: C3、When a BJT is operating in the active region, the voltage drop from the base to the emitter image.png is approximately equal to the （ ）。A:base bias voltageB:base current times the base resistorC:diode drop (about 0.7 V)D:emitter voltage答案: C4、BJTs are commonly used as （ ）.A:the primary components in amplifiersB:series damper circuitsC:the primary components in rectifiers答案: A5、The condition where increase in bias current will not cause further increases in collector current is called （ ）.A:cutoffB:saturationC:active operation答案: B第四章1、When a BJT is biased in the cutoff region the collector-to-emitter voltage is typically equal to （ ）.A:the emitter voltageB:03 VC:the collector current times the collector resistorD:the collector supply voltage答案: D2、Calculate the collector-emitter voltage for this emitter-stabilized circuit.（ ） image.pngA:32 VB:10.68 VC:1335 VD:14.24 V答案: 4.32 V3、The difference between the resulting equations for a network in which an npn transistor has been replaced by a pnp transistor is （ ）.A:the values of the resistorsB:the value of C:the sign associates with the particular quantities答案: C4、The term quiescent means （ ）.A:midpoint-biasedB:at restC:activeD:inactive答案: D5、Voltage-divider bias stability is （ ）.A:dependent on alphaB:dependent of betaC:dependent on the collector resistorD:independent of beta答案: D第五章1、Given this configuration, determine the input impedance if VS = 40 mV, Rsense = 0.5 k, and the input current is 20 A.（ ）image.pngA:5 MB:822 MC:1,500 D:582 k答案: C2、The image.png transistor model replaces the （ ） with the junction diodes ac resistance.A:collector-base junctionB:collector-emitter junctionC:emitterbase junction答案: C3、Calculate the voltage gain for this circuit. （ ）image.pngA:-137.25B:-8.4C: -7.91D:-16.34答案: A4、A transistor amplifier has an input signal applied to its emitter terminal and an output signal taken from its collector terminal. The amplifier is a(n) （ ）.A:common-emitter amplifierB:common-base amplifierC:common-collector amplifierD:emitter follower答案: B5、The voltage gain of a very well-designed common collector amplifier configuration, using a pnp transistor, is （ ）.A:about -0.9B:about 0.9C:in the range 0.95 to 0.99D:in the range -0.95 to -0.99答案: C第六章1、Shockleys equation defines the （ ） of the FET and are unaffected by the network in which the device is employed.A:image.png characteristicsB:drain characteristicsC:input/output characteristicsD:transfer characteristics答案: D2、For an n-channel depletion MOSFET, image.png= 8 mA and image.png = -6 V. If image.png= 0.8 V, what is the value of the drain current, image.png? （ ）A:8 mAB:10.25 AC:10.28 mAD:6 mA答案: C3、The region of the JFET drain curve that lies between pinch-off and breakdown is called （ ）.A:the constant-voltage regionB:the ohmic regionC:the saturation region答案: C4、In the family of FETs, you can expect to find （ ）.A:an n-channel typeB:a p-channel typeC:unipolar structure答案: ABC5、FETs usually （ ）.A:are less sensitive to temperature change than BJTsB:have a higher input impudence than BJTsC:are smaller in construction than BJTs答案: ABC第七章1、This graphical solution represents （ ）.image.pngA:fixed bias for an n-channel JFETB:voltage-divider bias for an n-channel JFETC:self bias for an n-channel JFET答案: C2、Generally, it is good design practice for linear amplifiers to have operating points that close to （ ）.A:are close to saturation levelB:the cut-off regionC:the midpoint of the load line答案: C3、Which of the following biasing circuits can be used with E-MOSFETs? （ ）A:self biasB:zero biasC:drain-feedback biasD:current-source bias答案: C4、The primary difference between JFETs and depletion-type MOSFETs is （ ）.A:JFETs can have positive values of image.png and levels of drain current that exceed image.pngB:depletion-type MOSFETs can have positive values of image.png and levels of image.png that exceed image.pngC:depletion-type MOSFETs can have only positive of image.pngD:JFETs can have only positive values of image.png答案:B5、A JFET can be biased in several different ways. The common method(s) of biasing an n-channel JFET is(are) （ ）.A:self-bias configurationB:voltage-divider bias configurationC:fixed-bias configuration答案: ABC第八章1、The FET version of the BJTs common-emitter configuration is the （ ） circuit.A:common-sourceB:common-gateC:common-drainD:common-current答案: A2、Calculate the input impedance for this FET amplifier. （ ）image.pngA:image.pngB:image.pngC:image.pngD:image.png = would depend on the drain current image.png答案: 3、Design this circuit for a voltage gain of 10. You have to calculate the value of resistor image.png and image.png. It is desired that the transistor operate with a relatively high value of image.png. For this device, a high value of image.png is defined as image.png. （ ）image.pngA:image.pngB:image.pngC:image.pngD:image.png答案: 4、The （ ） amplifier has high input impedance, low output impedance, and low voltage gain.A:common-gateB:common-drainC:common-source答案: B5、The （ ） FET amplifier has low input impedance, high output impedance, and high voltage gain.A:common-gateB:common-drainC:common-source答案: A第九章1、Calculate the low frequency break point due to the capacitor image.png for this BJT amplifier. （ ）image.pngA:image.pngB:image.pngC:image.pngD:image.png答案: 2、If several identical stages of amplifiers, each having the exact same upper and lower cutoff frequencies, are connected in cascade, then the bandwidth of the resulting amplifier will （ ）.A:increaseB:remain unchangedC:decreaseD:be equal to the sum of all the individual bandwidths答案: C3、A 3-dB drop in occurs at （ ）.A:image.pngB:image.pngC:image.pngD:image.png答案: 4、Negative dB values represent （ ）.A:power gainB:power lossesC:power values that do not change答案: B5、An amplifier has a midband power gain of 24,500. What is the value of the power gain in dB for the circuit? （ ）A:87.78 dBB:43.9 dBC:39 dB答案: B第十章1、Under difference-mode operation, the difference-mode voltage gain for this circuit is （ ）.image.pngA:0397B:80C:40D:08答案: C2、The operational amplifier will only slightly amplify signals （ ）.A:when the supply voltages are more then 25 VB:when the supply voltages are less then 5 VC:that are common on both the inputsD:that are different on both the inputs答案:C3、The inverting and noninverting inputs to an op-amp are used to drive a(n) （ ） amplifier.A:invertingB:noninvertingC:differentialD:open-loop答案: C4、When a given op-amp has a common-mode input of 10 V, the output of the device is 10 V. When the device has a differential input of 2 mV, the output of the device is 10 V. What is the CMPR of the device? （ ）A:5 : 1B:5000 : 1C:1000 : 1D:5,000,000 : 1答案: B5、The bandwidth of an amplifier is （ ）.A:the range of frequencies over which gain remains relatively constantB:the range of frequencies between the lower and upper 3 dB frequenciesC: the range of frequencies found using image.png答案: ABC第十一章1、 If the input voltage is 0.25 V and the output is -2.5 V, the value ofimage.png must be （ ）.image.pngA:40.0 kB:20.0 kC:16.0 kD:0 k答案: B2、The output voltage, VO, is given by （ ）.image.pngA:image.pngB:image.pngC:image.png答案: 3、A summing integrator is an op-amp integrator that has （ ）.A:multiple feedback capacitorsB:multiple input resistorsC:multiple input resistors and feedback capacitors答案: C4、A second order low-pass filter has a high-end roll-off of （ ）.A:60 dB/octaveB:40 dB/decadeC:20 dB/octaveD:6 dB/decade答案: B5、An active filter that provides a constant output for input signals above image.png is called an ideal （ ）.A:low-pass filterB:high-pass filterC:bandpass filter答案: B第十二章1、A class B amplifier (not push-pull) （ ）.A:conducts through 360 of the input waveformB:conducts through 180 of the input waveformC:conducts between 180 and 360 degrees of the input waveform, depending on the amount of dc biasD:conducts through less than 180 of the input waveform答案: B2、Crossover distortion in class B amplifiers is prevented by （ ）.A:biasing the transistors deeply into cutoffB:biasing the transistors slightly above cutoffC:using complementary-symmetry transistorsD:increasing the load resistance答案: B3、The maximum theoretical efficiency of an RC-coupled class A amplifier is （ ）.A:25%B:50%C:78.5%D:99%答案: A4、Power amplifiers are typically used to drive low impedance loads.（ ）A:对B:错答案: A5、The power that an amplifier delivers to a load is equal to the difference between the power that the circuit draws from the power supply and the power that the circuit dissipates.（ ）A:对B:错答案: A第十三章1、The feedback circuit connection shown here is （ ）.image.pngA:voltage series feedbackB:voltage shunt feedbackC:current series feedbackD:current shunt feedback答案: B2、Calculate the voltage gain for voltage series feedback when the amplifier gain is A = -2000 and F = -1/50. （ ）A:-2000B:-1/50C:50D:-48.78答案: D3、Calculate the input impedance for voltage series feedback when the amplifier has image.png = 10 k, amplifier gain is A = -2000, and F= image.png. （ ）A:input impedance with feedback 10 kB:input impedance with feedback 410 kC:input impedance with feedback 244 D:input impedance with feedback 50 答案: B4、The output impedance of current-shunt feedback amplifier （ ） the output impedance of its op-amp.A:is increased when compared toB:is decreased when compared toC:is reduced by half when compared toD:has no effect on答案: A5、An amplifier has a gain-bandwidth product of 200 MHz. A feedback network is added that has a feedback factor (1 + A) of 18.88. What is the gain-bandwidth product for the circuit with the added feedback network? （ ）A:10.59 MHzB:18.88 MHzC:200 MHz答案: C