# Elance Amplifiers And Filters Skill Test Questions

Question: 01
Which of the following bipolar transistor amplifier circuits is an FET amplifier common source circuit similar to?

a.     Common collector
b.     Common base
c.     Common mode
d.     Common emitter

Question: 02
For what portion of a signal cycle does a Class A amplifier operate?

a.     Exactly 180 degrees
b.     More than 180 degrees, but less than 360 degrees
c.     The entire cycle
d.     Less than 180 degrees

Question: 03
A high pass filter would normally be fitted:

a.     between the microphone and the speech amplifier
b.     at the Morse key or keying relay in a transmitter
c.     at the antenna terminals of the TV receiver
d.     between the transmitter output and the feed line

Question: 04
For what portion of a cycle does a Class B amplifier operate?

a.     Less than 180 degrees
b.     More than 180 degrees, but less than 360 degrees
c.     180 degrees
d.     The entire cycle

Question: 05
For what portion of a signal cycle does a Class C amplifier operate?

a.     More than 180 degrees, but less than 360 degrees
b.     Less than 180 degrees
c.     The entire cycle
d.     180 degrees

Question: 06
In the common collector amplifier, when the input and output signals are compared, the output signal leads the input signal by 90 degrees.

a.     True
b.     False

Question: 07
In the common emitter amplifier, when the input and output signals are compared, the output signal lags the input signal by 90 degrees.

a.     True
b.     False

Question: 08
Which of the following bipolar transistor amplifier circuits is an FET amplifier common drain circuit similar to?

a.     The common collector
b.     The common emitter
c.     The common base
d.     The common mode

Question: 09
An amplifier has a gain of 40 dB. The ratio of the rms output voltage to the rms input voltage is:

a.     20
b.     40
c.     100
d.     400

Question: 10
An attenuator network has 10 volt rms applied to its input with 5 volt rms measured as its output. The attenuation of the network is:

a.     6 dB
b.     10 dB
c.     20 dB
d.     40 dB

Question: 11
Which of the following is the principal use of an op-amp RC active filter circuitry?

a.     Op-amp circuits are used as low-pass filters at the output of transmitters
b.     Op-amp circuits are used as audio filters for receivers
c.     Op-amp circuits are used as filters for smoothing power supply output
d.     Op-amp circuits are used as high-pass filters to block RFI at the input of receivers

Question: 12
What are the advantages of a Darlington pair audio amplifier?

a.     High gain, high input impedance, and low output impedance
b.     Mutual gain, high stability, and low mutual inductance
c.     Mutual gain, low input impedance, and low output impedance
d.     Low output impedance, high mutual impedance, and low output current

Question: 13
For what portion of a cycle does a Class AB amplifier operate?

a.     Exactly 180 degrees
b.     The entire cycle
c.     Less than 180 degrees
d.     More than 180 degrees, but less than 360 degrees

Question: 14
What is a non-inverting op-amp circuit?

a.     An operational amplifier circuit connected in such a way that the input and the output signals are 90 degrees out of phase
b.     An operational amplifier circuit connected in such a way that the input and the output signals are in phase
c.     An operational amplifier circuit connected in such a way that the input impedance is held low and the output impedance is high
d.     An operational amplifier circuit connected such that the input and the output signals are 180 degrees out of phase

Question: 15
The input to an amplifier is 1 volt rms and the output 100 volt rms. This is an increase of:

a.     10 dB
b.     20 dB
c.     40 dB
d.     100 dB

Question: 16
In the common base amplifier, when the input and output signals are compared,_________?

a.     the output signal lags the input signal by 90 degrees
b.     the signals are in phase
c.     the output signals leads the input signal by 90 degrees
d.     the signals are 180 degrees out of phase

Question: 17
Which class of an amplifier operates over less than 180 degrees of the cycle?

a.     Class AB
b.     Class C
c.     Class A
d.     Class B

Question: 18
The input to an amplifier is 1 volt rms and the output 10 volt rms. This is an increase of:

a.     3 dB
b.     6 dB
c.     10 dB
d.     20 dB

Question: 19
What determines the gain of a closed-loop op-amp circuit?

b.     The power supply voltage
c.     The external feedback network
d.     The collector-to-base capacitance of the PNP stage

Question: 20
What is the input impedance of a theoretically ideal op-amp?

a.     Very low
b.     Exactly 100 ohms
c.     Exactly 1000 ohms
d.     Very high

Question: 21
What is an inverting op-amp circuit?

a.     An operational amplifier circuit connected in such a way that the input and the output signals are 180 degrees out of phase
b.     An operational amplifier circuit connected in such a way that the input and the output signals are in phase
c.     An operational amplifier circuit connected in such a way that the input and the output signals are 90 degrees out of phase
d.     An operational amplifier circuit connected in such a way that the input impedance is held to zero while the output impedance is high

Question: 22
Which class of an amplifier has the highest linearity and the least distortion?

a.     Class A
b.     Class AB
c.     Class B
d.     Class C

Question: 23
What determines the input impedance of an FET common- source amplifier?

a.     The input impedance is essentially determined by the resistance between the source and the substrate
b.     The input impedance is essentially determined by the resistance between the source and the drain
c.     The input impedance is essentially determined by the gate biasing network
d.     The input impedance is essentially determined by the resistance between the drain and the substrate

Question: 24
Which class of an amplifier provides the least efficiency?

a.     Class C
b.     Class B
c.     Class A
d.     Class AB

Question: 25
An attenuator network has 10 volt rms applied to its input with 1 volt rms measured as its output. The attenuation of the network is:

a.     6 dB
b.     10 dB
c.     20 dB
d.     40 dB

Question: 26
The FET amplifier source follower circuit is another name for a:

a.     Common source circuit
b.     Common drain circuit
c.     Common mode circuit
d.     Common gate circuit

Question: 27
Which of the following bipolar transistor amplifier circuits is an FET amplifier common gate circuit similar to?

a.     The common mode
b.     The common collector
c.     The common base
d.     The common emitter

Question: 28
An attenuator network comprises two 100 ohm resistors in series with the input applied across both resistors and the output taken from across one of them. The attenuation of the network is:

a.     3 dB
b.     6 dB
c.     50 dB
d.     100 dB

Question: 29
A filter that rejects all signals in the frequency band from zero frequency up to the required cut-off frequency is known as:

a.     a low pass filter
b.     a band pass filter
c.     a high pass filter
d.     a band reject filter

Question: 30
Which of the following terms is most appropriate for a high gain, direct-coupled differential amplifier the characteristics of which are determined by the components mounted externally?

a.     Difference amplifier
b.     Operational amplifier
c.     High gain audio amplifier
d.     Summing amplifier

Question: 31
What is an operational amplifier (op-amp)?

a.     A high-gain, direct-coupled audio amplifier the characteristics of which are determined by the components mounted externally
b.     A program subroutine that calculates the gain of an RF amplifier
c.     A high-gain, direct-coupled differential amplifier the characteristics of which are determined by the components mounted externally

Question: 32
Which class of an amplifier provides the highest efficiency?

a.     Class C
b.     Class A
c.     Class AB
d.     Class B

Question: 33
A low pass filter suitable for a high frequency transmitter would:

a.     pass audio frequencies above 3 kHz
b.     attenuate frequencies below 30 MHz
c.     attenuate frequencies above 30 MHz
d.     pass audio frequencies below 3 kHz

Question: 34
A filter that passes all signals in the frequency band from zero frequency up to the required cut-off frequency is known as:

a.     a low pass filter
b.     a high pass filter
c.     a band reject filter
d.     a band stop filter

Question: 35
Each stage of a three-stage amplifier provides a gain of 5 dB. The total amplification is:

a.     10 dB
b.     15 dB
c.     25 dB
d.     125 dB

Question: 36
Which class of an amplifier operates over the full cycle?

a.     Class A
b.     Class AB
c.     Class B
d.     Class C

Question: 37
What is meant by the term 'op-amp offset voltage'?

a.     The difference between the output voltage of the op-amp and the input voltage required for the next stage
b.     The potential between the amplifier input terminals of the op-amp in a closed-loop condition
c.     The potential between the amplifier input terminals of the op-amp in an open-loop condition
d.     The output voltage of the op-amp minus its input voltage

Question: 38
An amplifier with a gain of 20 dB has a 10 dB attenuator connected in cascade. The gain of the combination is:

a.     8 dB
b.     10 dB
c.     -10 dB
d.     -200 dB

Question: 39
What is the output impedance of a theoretically ideal op-amp?

a.     Very high
b.     Exactly 100 ohms
c.     Exactly 1000 ohms
d.     Very low

Question: 40
A transmitter power amplifier has a gain of 20 dB. The ratio of the output power to the input power is:

a.     10
b.     20
c.     40
d.     100