Module 1 study guide
ECET 257
This will not be collected for a grade. This is a complement to the in-class review session. Please complete ahead of time to
help identify the areas you need to review.
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) This is the symbol for a ________.
A) pnp-type BJT
1)
B) pnn-type BJT
C) npp-type BJT
D) npn-type BJT
2) In the active region, the base-emitter junction ________.
A) and the base-collector junctions are both forward-biased
B) is reverse-biased while the base-collector junction is forward-biased
C) and the base-collector junctions are both reverse-biased
D) is forward-biased while the base-collector junction is reversed-biased
2)
3) The common-base, short-circuit, amplification factor is better known as ________.
A) β
B) α
C) hfe
D) gos
3)
4) Which of the following expressions is true?
IC
A) αdc=
IE
4)
IC
B) αdc=
IB
ΔIC
C) αdc=
where VCE is constant
ΔIB
ΔIC
D) αdc=
where VCB is constant
ΔIE
5) In a small-signal transistor, the typical range of the parameter β is ________.
A) almost equal to 100 but always less than 100 (90 to 100)
B) large and in the range of about 50 to 400
C) greater than 100
D) between 0 and 100
5)
6) A BJT has measured dc current values of IB = 0.1 mA and IC = 8.0 mA. When IB is varied by 100
μA, IC changes by 10 mA. What is the value of the β dc for this device?
6)
A) 10
B) 80
C) 100
1
D) 800
7) Calculate the saturation collector current for this circuit.
A) 0.96 mA
B) 6.0 mA
C) 0.056 mA
7)
D) 0.904 mA
8) Calculate the base current for this emitter-stabilized bias circuit.
A) 0.119 mA
C) 89.0 mA
8)
B) 89.1 μA
D) None of the above
9) The difference between the resulting equations for a network in which an npn transistor has been
replaced by a pnp transistor is ________.
A) the sign associated with the particular quantities
B) the value of β
C) the values of the resistors
D) All of the above
9)
10) A(n) ________ is added to the fixed-bias configuration to improve bias stability.
A) collector resistor
B) base voltage
C) emitter resistor
D) All of the above
10)
11) The input impedance of a BIT is ________.
A) capacitive
B) resistive
C) inductive
D) a combination of resistive, capacitive, and inductive
11)
2
12) Determine the input impedance for this two-port network when VS = 50 mV, Ii = 20 μA, and
12)
Rsense = 500Ω.
A) 2.0 MΩ
B) 20.0 kΩ
C) 200.0 kΩ
D) 2000 Ω
13) The re transistor model replaces the ________ with the junction diode's ac resistance.
A) collector-emitter junction
B) emitter∙base junction
C) collector-base junction
D) All of the above
13)
14) Calculate the voltage gain for this circuit.
14)
A) -8.4
B) -16.34
C) -7.92
D) -201.34
15) For the cascaded amplifier shown here, the output voltage Vo2 is ________ the input voltage Vi3.
A) exactly equal to
C) much larger than
B) less than
D) larger than
3
15)
16) An common emitter fixed bias amplifer circuit is not working. When measurements are made, VB
is found to be 0.4V higher than VE, and VE is 0V. Engineer A says an open RB could cause this.
Engineer B says a damaged transistor could cause this. Who is right?
A) Engineer A
B) Engineer B
C) Both
D) Neither
16)
17) A CE amplifer has a voltage gain of -320 when unloaded, but a voltage gain of -180 when the load
is connected. Engineer A says this is normal. Engineer B says a open RC could be the cause. Who
is right?
A) Engineer A
B) Engineer B
C) Both
D) Neither
17)
4
Answer Key
Testname: SG_MODULE1
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2)
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A
D
B
A
B
B
B
B
A
C
B
D
B
D
A
B
A
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