Renñier A.
Salvador
BSECE 4-5
PROBLEM SET: Elex05
1.
A BJT has a collector current of 10 mA and a current gain (β) of 100. What is the
base current (Ib)?
A) 100 µA
B) 200 µA
C) 1 mA
D) 10 mA
Answer: B
2.
For a common-emitter amplifier, the collector resistor is 2 kΩ, and the supply
voltage is 12 V. If the collector current is 3 mA, what is the voltage drop across the
collector resistor?
A) 6 V
B) 4 V
C) 2 V
D) 1 V
Answer: A
3.
In a BJT, the emitter current is 5 mA, and the current gain (β) is 150. What is the
collector current (Ic)?
A) 5 mA
B) 7.5 mA
C) 10 mA
D) 15 mA
Answer: A
4.
In a common-base configuration, the input current is 2 mA. If the current gain (α)
is 0.98, what is the output current?
A) 1.96 mA
B) 2.02 mA
C) 3.02 mA
D) 1.02 mA
Answer: A
5.
A transistor has a collector-emitter voltage (Vce) of 8 V, a collector current (Ic) of
20 mA, and a base-emitter voltage (Vbe) of 0.7 V. What is the power dissipated by
the transistor?
A) 0.14 W
B) 0.28 W
C) 0.56 W
D) 1 W
Answer: B
6.
What is the voltage gain of a common-emitter amplifier with a collector resistance
of 1.5 kΩ and a transconductance of 50 mA/V?
A) 10
B) 50
C) 75
D) 100
Answer: A
7.
In a transistor amplifier circuit, the base voltage is 1.2 V, and the base-emitter
voltage (Vbe) is 0.7 V. What is the emitter voltage?
A) 0.5 V
B) 1.2 V
C) 1.4 V
D) 2.0 V
Answer: A
8.
A BJT has a collector current of 20 mA, and the voltage drop across the collector
resistor is 4 V. What is the supply voltage if the emitter voltage is 2 V?
A) 10 V
B) 8 V
C) 6 V
D) 4 V
Answer: A
9.
In a common-emitter amplifier, the input voltage is 1 mV, and the voltage gain is
100. What is the output voltage?
A) 1 V
B) 10 V
C) 100 mV
D) 10 mV
Answer: A
10.
If the emitter resistor in a common-emitter amplifier is 1 kΩ and the collector
current is 2 mA, what is the voltage drop across the emitter resistor?
A) 1 V
B) 2 V
C) 0.5 V
D) 2.5 V
Answer: B
11.
For a JFET, the drain current (Id) is 4 mA, and the gate-source voltage (Vgs) is -2
V. If the pinch-off voltage is -3 V, what is the type of the FET?
A) N-channel
B) P-channel
C) Depletion-type
D) Enhancement-type
Answer: B
12.
In an FET circuit, the gate-source voltage is 2 V, and the drain current is 5 mA.
What is the transconductance (gm) of the transistor?
A) 0.5 mA/V
B) 5 mA/V
C) 0.1 mA/V
D) 1 mA/V
Answer: A
13.
A MOSFET has a drain-source voltage (Vds) of 10 V and a drain current (Id) of 2
mA. The gate-source voltage (Vgs) is 3 V. What is the threshold voltage?
A) 1.5 V
B) 2 V
C) 3 V
D) 4 V
Answer: A
14.
A FET has a pinch-off voltage of -5 V. What will happen to the drain current if the
gate-source voltage is reduced below the pinch-off voltage?
A) The drain current increases
B) The drain current decreases
C) The drain current becomes zero
D) The transistor stops functioning
Answer: C
15.
For an N-channel MOSFET, the gate-source voltage is 4 V, and the threshold
voltage is 2 V. What is the drain current if the drain-source voltage is 5 V?
A) 3 mA
B) 2 mA
C) 1 mA
D) 4 mA
Answer: A
16.
In a JFET, the maximum drain current (Id(max)) is 6 mA, and the gate-source
voltage is -1 V. What will be the drain current when the gate-source voltage is -2 V?
A) 4 mA
B) 3 mA
C) 2 mA
D) 1 mA
Answer: B
17.
What happens to the current in a MOSFET when the gate-source voltage exceeds
the threshold voltage?
A) The current decreases
B) The current remains constant
C) The current increases
D) The current becomes zero
Answer: C
18.
The drain current in a MOSFET is given by Id = k(Vgs - Vth)^2. If Vgs = 6 V and
Vth = 3 V, and the constant k is 0.2 A/V², what is the drain current?
A) 0.36 A
B) 0.24 A
C) 0.36 mA
D) 0.48 mA
Answer: C
19.
For a P-channel MOSFET, when the gate-source voltage (Vgs) is 1 V and the drain-
source voltage (Vds) is 5 V, what is the mode of operation?
A) Cutoff
B) Saturation
C) Linear
D) Sub-threshold
Answer: B
20.
In an FET, what is the function of the gate terminal?
A) It controls the current flow between drain and source
B) It provides power to the circuit
C) It serves as a heat sink
D) It amplifies the signal
Answer: A
21.
In a common-emitter amplifier, the AC voltage gain is 50. If the input signal is 0.1
V, what is the output voltage?
A) 0.5 V
B) 5 V
C) 50 V
D) 100 V
Answer: B
22.
What is the overall voltage gain of a cascaded amplifier with gains of 10 and 20?
A) 200
B) 30
C) 10
D) 2000
Answer: A
23.
In an amplifier with a power supply of 12 V and a load resistor of 1 kΩ, the
collector current is 2 mA. What is the power delivered to the load resistor?
A) 4 mW
B) 2 mW
C) 10 mW
D) 1 mW
Answer: A
24.
A differential amplifier has a common-mode rejection ratio (CMRR) of 80 dB. What
is the ratio of the differential gain to the common-mode gain?
A) 10
B) 100
C) 1000
D) 10000
Answer: C
25.
For an operational amplifier with a gain of 100, if the input voltage is 0.02 V, what
is the output voltage?
A) 2 V
B) 0.2 V
C) 0.02 V
D) 1 V
Answer: A
26.
The output resistance of an amplifier is 100 Ω, and the load resistance is 500 Ω.
What is the overall voltage gain if the open-loop voltage gain is 50?
A) 30
B) 40
C) 45
D) 50
Answer: A
27.
If the input signal to an amplifier is 5 mV and the output signal is 1 V, what is the
voltage gain?
A) 200
B) 100
C) 500
D) 50
Answer: A
28.
An amplifier has a bandwidth of 10 kHz and a gain of 1000. What is the total power
bandwidth?
A) 10 kHz
B) 100 kHz
C) 1000 kHz
D) 1 MHz
Answer: B
29.
In a common-collector amplifier, the voltage gain is:
A) Less than 1
B) Equal to 1
C) Greater than 1
D) Infinite
Answer: A
30.
In an amplifier with a gain of 100, if the input signal is 0.5 V, what is the output
voltage?
A) 5 V
B) 50 V
C) 500 V
D) 0.5 V
Answer: A
31.
In a transistor amplifier, the collector resistor is 2 kΩ and the supply voltage is 12
V. If the voltage drop across the collector resistor is 4 V, what is the collector
current?
A) 2 mA
B) 4 mA
C) 6 mA
D) 8 mA
Answer: A
32.
The input resistance of a common-emitter amplifier is 2 kΩ, and the load resistance
is 5 kΩ. What is the total resistance seen by the source?
A) 2 kΩ
B) 5 kΩ
C) 7 kΩ
D) 10 kΩ
Answer: C
33.
A transistor amplifier has a voltage gain of 50, and the input signal is 0.1 V. What
is the output voltage?
A) 5 V
B) 10 V
C) 50 V
D) 0.5 V
Answer: A
34.
What is the total current gain in a cascaded amplifier with current gains of 10 and
20?
A) 200
B) 10
C) 30
D) 50
Answer: A
35.
In a common-emitter amplifier, if the collector current is 4 mA, and the collector
resistor is 2 kΩ, what is the voltage drop across the collector resistor?
A) 8 V
B) 4 V
C) 2 V
D) 1 V
Answer: A
36.
If the input impedance of an amplifier is 500 Ω and the output impedance is 1 kΩ,
what is the overall impedance of the amplifier circuit?
A) 500 Ω
B) 1 kΩ
C) 1.5 kΩ
D) 1.8 kΩ
Answer: C
37.
In an amplifier, the input voltage is 10 mV, and the output voltage is 500 mV. What
is the voltage gain?
A) 100
B) 500
C) 50
D) 10
Answer: B
38.
In an amplifier circuit, the current gain is 20, and the input current is 2 mA. What
is the output current?
A) 10 mA
B) 20 mA
C) 40 mA
D) 2 mA
Answer: A
39.
In a differential amplifier, the differential gain is 100, and the common-mode gain
is 2. What is the common-mode rejection ratio (CMRR)?
A) 100
B) 50
C) 200
D) 50 dB
Answer: D
40.
The input voltage to an amplifier is 5 V, and the voltage gain is 10. What is the
output voltage?
A) 50 V
B) 5 V
C) 0.5 V
D) 10 V
Answer: A
41.
The open-loop voltage gain of an op-amp is 100,000, and the feedback factor is
0.01. What is the closed-loop gain?
A) 100
B) 10
C) 1000
D) 10,000
Answer: A
42.
What happens to the gain of an amplifier if the load resistance is decreased while
keeping other parameters constant?
A) The gain increases
B) The gain decreases
C) The gain remains the same
D) The amplifier will stop working
Answer: B
43.
In a power amplifier, the collector voltage is 12 V, and the load resistance is 4 Ω.
What is the power delivered to the load resistor if the current is 3 A?
A) 36 W
B) 72 W
C) 144 W
D) 9 W
Answer: B
44.
In a transistor amplifier, if the voltage gain is 40 and the input voltage is 0.5 V,
what is the output voltage?
A) 20 V
B) 50 V
C) 40 V
D) 80 V
Answer: D
45.
In a BJT amplifier, the input signal is 5 mV, and the gain is 200. What is the output
signal?
A) 1 V
B) 100 V
C) 5 V
D) 1000 V
Answer: A
46.
For a common-collector amplifier, the voltage gain is less than 1. What is the type
of the amplifier?
A) Voltage amplifier
B) Current amplifier
C) Buffer amplifier
D) Both B and C
Answer: D
47.
An amplifier has a current gain of 25, and the input current is 2 mA. What is the
output current?
A) 25 mA
B) 50 mA
C) 500 mA
D) 5 mA
Answer: A
48.
What is the impedance of an emitter follower circuit if the emitter resistor is 1 kΩ
and the transistor's internal impedance is 100 Ω?
A) 100 Ω
B) 1 kΩ
C) 110 Ω
D) 1000 Ω
Answer: C
49.
In a common-emitter amplifier, the voltage drop across the emitter resistor is 2 V,
and the supply voltage is 12 V. If the collector resistor is 4 kΩ, what is the collector
current?
A) 2 mA
B) 3 mA
C) 4 mA
D) 5 mA
Answer: A
50.
If a BJT amplifier has a collector current of 5 mA, a collector resistor of 2 kΩ, and a
supply voltage of 12 V, what is the voltage drop across the collector resistor?
A) 8 V
B) 10 V
C) 5 V
D) 2 V
Answer: A
