(8.2.4)--Chapter 4 DC Biasing-BJTS模拟电子技术基础.doc

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1、Chapter 4: DC Biasing-BJTS1) When a BJT is biased in the active region, its base-emitter junction is _-biased and its collector-base junction is _-biased. A) forward; reverse B) reverse; forward C) forward; forward D) reverse; reverse 2) When a BJT is biased in the cut-off region, its base-emitter j

2、unction is _-biased and its collector-base junction is _-biased. A) forward; reverse B) reverse; forward C) forward; forward D) reverse; reverse 3) When a BJT is biased in the saturation region, its base-emitter junction is _-biased and its collector-base junction is _-biased. A) forward; reverse B)

3、 reverse; forward C) forward; forward D) reverse; reverse 4) Calculate the base current for this circuit. A) 0.904 mA B) 0.96 mA C) 0.056 mA D) 6.0 mA 5) Calculate the maximum collector current for this circuit. A) 0.904 mA B) 0.96 mA C) 0.056 mA D) 6.0 mA 6) When a BJT is biased in the cutoff regio

4、n the collector-to-emitter voltage is typically equal to _. A) the emitter voltage B) 0.03 V C) the collector current times the collector resistor D) the collector supply voltage 7) This emitter-stabilized bias circuit is operating in the _. A) saturation region B) cutoff region C) active region D)

5、The transistor is not properly biased. 8) Calculate the base current for this emitter-stabilized bias circuit. A) 89.0 mA B) 89.0 A C) 0.119 mA D) None of the above 9) Calculate the collector-emitter voltage for this emitter-stabilized circuit. A) 4.32 V B) 10.68 V C) 0.1335 V D) 14.24 V 10) Calcula

6、te the base current for this voltage-divider bias circuit. A) 233.78 A B) 34.62 A C) 596.55 A D) 76.8 A 11) When voltage-divider bias is used, it is considered appropriate to use the approximate analysis to determine the bias condition when the resistance R2 is _ (1+ )RE.A) greater than B) less than

7、 C) very much greater than D) very much less than 12) Calculate the base current for this circuit. A) 28.4 A B) 20.2 A C) 28.3 A D) Need more information to calculate the base current 13) When designing a current-gain-stabilized voltage-divider bias circuit such as this one, the rule of thumb used f

8、or the emitter voltage is _. A) VE = VCC / 10 B) VCE = VCC / 10 C) VB = VCC / 10 D) VC = VCC / 10 14) When a BJT transistor is used in a switching circuit, it operates in the _. A) saturation and active regions B) active and cutoff regions C) saturation and cutoff regions D) active region only 15) T

9、he 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 resistors B) the value of C) the sign associates with the particular quantities D) All of the above 16) When a BJT has its base-emitter junction for

10、ward biased and its collector-base junction reverse biased, it is biased in the _. A) saturation region B) active region C) cutoff region D) passive region 17) When a BJT has its base-emitter junction reverse biased and its base-collector junction forward biased, it is biased in the _. A) saturation

11、 region B) active region C) cutoff region D) passive region 18) When a BJT has its base-emitter junction forward biased and its collector-base junction also forward biased, it is in the _. A) saturation region B) active region C) cut-off region D) passive region 19) When a BJT has its base-emitter j

12、unction reverse biased and its collector-base junction reverse biased, it is in the _. A) saturation region B) active region C) cutoff region D) passive region 20) The term quiescent means _. A) midpoint-biased B) at rest C) active D) inactive 21) The base current for this circuit is _. A) 6 mA B) 1

13、.37 mA C) 1.13 mA D) 12 mA 22) The maximum collector current for this circuit is _. A) 1.13 mA B) 12 mA C) 6 mA D) 1.0 mA 23) When a BJT is in cutoff, the collector-to-emitter voltage is typically equal to _. A) collector supply voltage B) collector current times collector resistor C) 0.3 Volts D) e

14、mitter voltage 24) The change in and VCE that can occur when the temperature changes is known as _. A) midpoint bias B) midpoint movement C) output movement D) Q-point movement 25) A(n) _ is added to the fixed-bias configuration to improve bias stability. A) base voltage B) emitter resistor C) colle

15、ctor resistor D) All of the above 26) The input resistance of a stabilized fixed-bias circuit configuration is _. A) inversely related to the emitter resistor B) inversely related to C) directly related to the collector resistor D) directly related to the emitter resistor 27) Two of the factors asso

16、ciated with bias stability are _. A) voltage and current B) the and the junction temperature C) age and amount of use D) None of the above 28) When a transistor is in saturation, the total collector current is limited by _. A) collector supply voltage and the total resistance in the collector and em

17、itter circuits B) collector-to-emitter and collector supply voltage C) collector supply, collector-to-emitter voltage, and the total collector circuit resistance D) the transistor 29) Voltage-divider bias stability is _. A) dependent on alpha B) dependent of beta C) dependent on the collector resist

18、or D) independent of beta 30) Collector-feedback bias _. A) provides a feedback path from collector to base B) provides an improved level of stability C) is not totally independent of beta D) All of the above 31) The collector-feedback bias configurations input resistance is related to the _. A) emi

19、tter resistor B) collector resistor C) device beta D) base feedback resistor 32) The emitter-follower configuration has _. A) a 180 phase shift B) an output voltage slightly greater than the input voltage C) the emitter connected to dc ground potential D) None of the above 33) A collector-feedback b

20、ias circuit is found to be in saturation. Which of the following could cause this condition? A) The base resistor is open. B) The collector resistor is open. C) The transistor is shorted base-to-emitter. D) A solder bridge across the base resistor. 34) In the design of an emitter-bias stabilized cir

21、cuit engineering, judgment must be used because the _. A) collector resistor is usually unknown B) emitter resistor is usually unknown C) relative voltage levels have not been defined D) All of the above 35) When designing for best bias stability the _ configuration should be chosen. A) voltage-divi

22、der bias B) collector-feedback bias C) fixed-bias D) emitter-feedback bias 36) When designing a voltage-divider bias circuit, the divider resistors _. A) should carry approximately equal current B) should carry currents that are 10 times the base current C) determine the base voltage as the drop acr

23、oss base-common resistor D) All of the above 37) Why is design for a specific bias point desirable for most amplifiers? A) To meet manufacturer suggested opening point. B) It allows optimum ac operation of the circuit. C) It allows optimum dc operation of the circuit. D) All of the above 38) There a

24、re transistors that are called switching transistors because _. A) they have a built in switch B) of the speed at which they can be changed from on to off C) of the power they can transfer from input to output D) of the voltage they can transfer from input to output 39) Transistor circuits that are

25、quite stable and relatively insensitive to temperature variations have _. A) relative high supply voltages B) low supply voltages C) large betas D) small betas 40) To design a transistor circuit for maximum stability, one must consider _. A) the collector leakage current stability factor B) the base

26、-emitter junction voltage stability factor C) the transistors beta stability factor D) All of the above 41) Variation in hfe is influenced by _. A) junction temperature and collector current B) temperature and base current C) bias type and device size D) device size and base current ANSWER KEY: Chapter 4: DC Biasing-BJTs 1) A 2) D 3) C 4) A 5) D 6) D 7) A 8) C 9) A 10) C 11) C 12) B 13) A 14) C 15) C 16) B 17) C 18) A 19) C 20) D 21) C 22) C 23) A 24) D 25) B 26) D 27) B 28) A 29) D 30) D 31) C 32) D 33) C 34) D 35) A 36) D 37) D 38) B 39) C 40) D 41) A