；is less than the specified；

C.the applied voltage is greater than；

D.All of these

正确答案：All of these

第三章单元测试

1、In the active region， the base-emitter junction（）.

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 reverse-biased while the base-collector junction is forward-biased

正确答案：is forward-biased while the base-collector junction is reversed-biased

2、A BJT has measured dc current values of

= 0.1 mA and

= 8.0 mA.When IB is varied by 100 μA， IC changes by 10 mA.What is the value of the βac for this device？（）.

A.80

B.10

C.100

D.800

正确答案：100

3、When a BJT is operating in the active region， the voltage drop from the base to the emitter

is approximately equal to the（）。

A.base bias voltage

B.base current times the base resistor

C.diode drop（about 0.7 V）

D.emitter voltage

正确答案：diode drop（about 0.7 V）

4、BJTs are commonly used as（）.

A.the primary components in amplifiers

B.series damper circuits

C.the primary components in rectifiers

正确答案：the primary components in amplifiers

5、The condition where increase in bias current will not cause further increases in collector current is called（）.

A.cutoff

B.saturation

C.active operation

正确答案：saturation

第四章单元测试

1、When a BJT is biased in the cutoff region 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

正确答案：the collector supply voltage

2、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

正确答案：4.32 V