西安邮电大学
- Electrons are the minority carriers in an n-type material.（ ）
- The output impedance of a BJT amplifier tends to be much less than that of a comparable FET amplifier.（ ）
- To design a transistor circuit for maximum stability, one must consider （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/ae800ecf583348eeba62687719759446.png
- Why is design for a specific bias point desirable for most amplifiers? （ ）
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/d85c2194d1164acbb1db3af2c203747e.png
- The input stage of an integrated operational amplifier is generally composed of （ ） .
- The output of an op-amp voltage buffer is characterized by （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/cc9a73ea39df4ee89fe07b6fa1e00735.png
- CMRR is a main technical index of differential amplifier circuit, reflects （ ） the ability of amplifier circuit.
- A class B push-pull amplifier （ ）.
- The input impedance for a common-emitter configuration can be expressed as ( ).
- When designing for best bias stability the （ ） configuration should be chosen.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/5e46788d008440a3930a5a10b620c72d.png
- A given BJT has an emitter current of 15 mA and a collector current of 14.95 mA. What is the exact value of β?（ ）
- Which of the following are properties of logarithms'?（ ）
- The input impedance of a voltage-shunt feedback amplifier （ ） the input impedance of its op-amp.
- Amplifier ac input and output currents are （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/8c843e4e09794ff892aa1c319281844a.png
- Which of the following expressions is true? （ ）
- When a p-n junction is reverse-biased, the depletion layer is ________ and the device acts as a near-perfect ________（ ）.
- In the saturation region, the base-emitter junction （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/96507fcb6e854c5695c225d7ba712b9e.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/c9afd1da9e004f1ca7c8f5aaf22b9265.png
- Voltage-series negative feedback （ ） the bandwidth of an op-amp.
- When a BJT is in cutoff, the collector-to-emitter voltage is typically equal to （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/c48eaaf0ea044bffa9a8e1e001038be3.png
- The electrode with n-type material of a diode is called the ( ).
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/b48447c7749845ebac1475c1b9159cb8.png
- The maximum possible efficiency of a class A amplifier is equal to （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/d5fab07ebb9d4f2e8257b56d48017d29.png
- The self-bias configuration develops the controlling gate-to-source voltage across a resistor introduced in the （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/79352cedf3e44340a710f92443f20e42.png
- The op-amp circuit that add each input and multiplies the sum by a fixed amount is called a(n) （ ）.
- A given BJT, β = 400. What is the value of α for the device? （ ）
- Depending on the configuration of the amplifier, the magnitude of the no-load voltage gain for a single BJT transistor amplifier typically ranges from （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/a9833b91b1624216aa3e8e342242e619.png
- A class A amplifier （ ）.
- The diffusion capacitance of a diode is a shunt capacitance effect that occurs when the diode（ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/10c6e32b1cb848c88e3aaba46c2ce689.png
- Depending on the configuration of the amplifier, the magnitude of the no-load current gain for a single BJT transistor amplifier typically ranges from （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/526438921fa14f54af357fdf91f0f1fc.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/2dec76cd000d4cfb981fac088b120da7.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/5a7be9dcaac44c15b4ada6b77388d64e.png
- A class C amplifier （ ）.
- Many MOSFET devices now contain internal （ ） that protect them from static electricity.
- MOSFETs are also referred to as （ ）.
- Which of the following FETs is the best choice when the gate-source voltage has both positive and negative swings? （ ）
- The fixed-bias technique requires （ ） power supplies.
- The transition capacitance of a diode is a shunt capacitive effect that occurs when the diode （ ）.
- The JFET is a （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/ce11af6424604a7990c81be414b3ede6.png
- With transformer coupling the maximum theoretical efficiency of a class A amplifier can be increased up to （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/8e1fb9da86f84e9b94e30e4f9e142a98.png
- If the resistor in the emitter leg is not bypassed by a capacitor then the voltage gain of the small signal amplifier will （ ）.
- When a p-n junction's depletion layer is narrowed and the device acts as a nearly perfect conductor, it is （ ）.
- An op-amp integrator circuit has a 2 MΩ input resistor and a 5 μF feedback loop capacitor. If the inverting input voltage is 2 VDC, the final value of the output voltage is （ ）.
- Amplifier ac input and output voltages are （ ）.
- Generally, it is a good design practice for linear amplifiers to choose the operating point that is approximately （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/180701c2a792465797e8121f6c55b6fe.png
- The term semi-log refers to a graphical scale that has （ ）.
- The enhancement-type and the depletion-type FETs are subclasses of （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/612722b46aab472fa26ec978d2f557b6.png
- An op-amp high-pass active filter provides a constant output （ ）.
- For a two-port system, like a BJT amplifier, the no-load voltage gain （ ）.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/1127ade5f3174e38bdc627acb52e97c5.png
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/7b3bec6a041643a28edfb677a10bfd0d.png
- A(n) （ ） is added to the fixed-bias configuration to improve bias stability.
- The ideal diode symbol has an arrow that points in the direction of （ ）.
- Which transistor amplifier configuration has a 180° voltage phase shift from input to output? （ ）
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/85b63fcfd70a47438336926cf00e8dde.png
- In the integrated operational amplifier circuit, the （ ） coupling mode is adopted between the circuit of all levels.
- Which transistor amplifier configuration is the most commonly used? （ ）
- In a fixed-bias circuit for an n-channel JFET transistor the bias line （ ）.
- For basic operation of a transistor the collector-base junction is （ ） biased.
- http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/a4d628ce5f3c4854b39f9512fd5da310.png
- Transistor circuits that are quite stable and relatively insensitive to temperature variations have （ ）.
- The input impedance of a common-base BJT configuration is typically ( ).
- Current-series feedback （ ） the output impedance of an op-amp.
- As the channel width of a JFET decreases, the source-to-drain resistance （ ）.
A:错 B:对
答案:错
A:对 B:错
答案:错
A:the transistor's beta stability factor B:the collector leakage current stability factor C:the base-emitter junction voltage stability factor
答案:A/B/C
A:
= 0
B:
is open
C:R is shorted by a solder bridge答案:R is shorted by a solder bridge###http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/4867d36f3369437c86a2c4d0e970ec7e.png###http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/b2005f610f1e48dd8c078703fd3b7f44.png
A:It allows optimum ac operation of the circuit. B:It allows optimum dc operation of the circuit. C:To meet manufacturer suggested opening point.
答案:It allows optimum dc operation of the circuit.###It allows optimum ac operation of the circuit.###To meet manufacturer suggested opening point.
A:has a very positive B:has a very negative C:has no D:may be positive or negative and depends on the rest of the circuit
答案:has a very positive
A:power amplifier circuit B:voltage amplifier circuit C:differential amplifier circuit D:current source
答案:C:differential amplifier circuit
A:
B:
C:
D:
答案:
A:8.6 mA B:9.6 mA C:7.6 mA D:6.68 mA
答案:6.68 mA
A:eliminate distortion B:Enlarging Differential Mode and Suppressing Common Mode C:high input resistance D:low output resistance
A:works only with digital and pulsed waveforms B:conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias C:conducts through less than 180° of the input waveform D:conducts through 180° of the input waveform
A:
B:
C:
D:
A:emitter-feedback bias B:collector-feedback bias C:fixed-bias D:voltage-divider bias
A:-16.34 B: -7.91 C: -137.25 D:-8.4
A:299 B:250 C:1.003 D:300
A:
B:
C:
A:is decreased when compared to B:is reduced by half when compared to C:has no effect on D:is increased when compared to
A:always in phase B:180° out of phase in all but one amplifier configuration C:always 180°s out of phase D:in phase in all but one amplifier configuration
A:voltage feedback ratio B:input impedance C:small-signal current gain D:output admittance
A:
B:
where 
is constant
D:
where 
is constant
A:narrowed; conductor B:widened; conductor C:widened; insulator D:narrowed; insulator
A:and the base-collector junctions are both forward-biased B:and the base-collector junctions are both reverse-biased C:is forward-biased while the base-collector junction is reversed-biased D:is reversed-biased while the base-collector junction is forward-biased
A:500 μ.S B:300 μ.S C:Cannot be determined from the information given D:1200 μ.S
A:the collector current times the collector resistor B:zero (about 0.3 Volts) C:the collector supply voltage D:the emitter voltage
A:has no effect on B:reduces by half C:decreases D:increases
A:collector supply voltage B:emitter voltage C:0.3 Volts D:collector current times collector resistor
A:negative half cycle of the input waveform B:entire input waveform C:The diode will block all current and there will be no current flowing through the load D:positive half cycle of the input waveform
A:Zener region B:cathode C:anode D:depletion region
A:1 B:0 C:3 D:2
A:30% B:20% C:25% D:15
A:2.0 MΩ B:200.0 kΩ C:20.0 kΩ D:2000 Ω
A:gate leg B:source leg C:drain leg
A:The transistor is not properly biased. B:cutoff region C:active region D:saturation region
A:summing amplifier B:unity follower C:differentiator D:integrator
A:1.0025 B:1.00 C:0.9975 D:0.002
A:a hundred to about a million B:just a little less than 1 to a few hundred C:10 to about 10,000
A:34.8 dB B:3000 dB C:69.5 dB
A:conducts through 360° of the input waveform B:conducts through 180° of the input waveform C:conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias D:conducts through less than 180° of the input waveform
A:is small B:is reverse biased C:is large D:is forward biased
A:
B:
C:
D:
A:10 to about 10,000 B:one to about a thousand C:just a little less than 1 to a level that may exceed one hundred
A:0.1 B:10 C:-10 D:-0.1
A:self bias for an n-channel JFET B:fixed-bias configuration for an n-channel JFET C:voltage-divider bias for an n-channel JFET
A:0.0001 B:80 C:0.000125 D:Cannot be determined from the information given
A:works only with digital and pulsed waveforms B:conducts through less than 180° of the input waveform C:conducts between 180° and 360° degrees of the input waveform, depending on the amount of dc bias D:conducts through 180° of the input waveform
A:p-n junction diodes B:BJTs C:capacitors D:Zener diodes
A:substrates B:DEFETs C:IGFETs D:SiO-FETs
A:depletion MOSFET B:CMOS C:enhancement MOSFET D:JFET
A:2 B:3 C:4 D:1
A:is large B:is small C:is forward-biased D:is reverse-biased
A:power-controlled device B:frequency-controlled device C:voltage-controlled device D:current-controlled device
A:bandpass filter B:high-pass filter C:low-pass filter
A:60% B:50% C:55% D:45%
A:goes to zero B:increases C:remains the same D:decreases
A:increase in some cases and decrease in other cases B:decrease C:increase D:stay the same
A:forward-biased B:unbiased C:reverse-biased
A:-0.2 V B:-20 V C:-2 V D:0.02 V
A:180° out of phase in all but one amplifier configuration B:in phase in all but one amplifier configuration C:always 180° out of phase D:always in phase
A:near the saturation region B:near the cut-off region C:in the center of the active region D:near the origin
A:
B:
C:
D:
A:a linear vertical axis and a log horizontal axis B:a log-log structure C:a linear axis and a log axis
A:bipolar FETs B:BJTs C:junction FET D:metal-oxide-semiconductor FETs
A:0.133 B:66.66 C:33.33 D:0.266
A:from
to 
B:from dc to
C:from dc to infinite frequency
D:for all frequencies higher then 
A:is always less than the loaded voltage gain B:is always greater than the loaded voltage gain C:can be less than or equal to the loaded voltage gain D:is always equal to the loaded voltage gain
A:1 : 1 B:It can be done in practice by making
much larger than 
C:2 : 1
D:1: 2
A:40 mV B:35 mV C:30 mV
A:base voltage B:emitter resistor C:collector resistor
A:the leakage current flow B:positive terminal under forward bias C:the forward current flow
A:common-collector B:common-emitter C:common-base
A:16.97 mA during the negative half cycle B:12 mA during the positive half cycle C:16.97 mA during the positive half cycle D:12 mA during the negative half cycle
A:transformer B:photoelectricity C:resistance capacitance D:direct
A:common-collector B:common-base C:None of these are used more often than the others D:common-emitter
A:is straight left and right parallel to the
axis
B:is straight up and down parallel to the 
axis
C:is slanted and passes through origin
D:is slanted and passing through the 
and the 
axis on the positive side
A:not B:reverse- C:forward- D:semi-
A:
B:
C:
D:
A:low supply voltages B:large betas C:small betas D:relative high supply voltages
A: less than 50 Ω B: between 100 Ω and 100 kΩ C: between 100 kΩ and 10 MΩ D: so large that the input current can be considered to be zero
A:has no effect on B:increases C:reduces by half D:decreases
A:increases B:decreases C:remains constant D:is not affected
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