Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ham Extra 2016-2020 > E7 Practical Circuits > Flashcards

E7 Practical Circuits Flashcards

1
Q

E7A01 (C) Which is a bi-stable circuit?

A

C. A flip-flop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

E7A02 (A) What is the function of a decade counter digital IC?

A

A. It produces one output pulse for every ten input pulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

E7A03 (B) Which of the following can divide the frequency of a pulse train by 2?

A

B. A flip-flop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

E7A04 (B) How many flip-flops are required to divide a signal frequency by 4?

A

B. 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

E7A05 (D) Which of the following is a circuit that continuously alternates between two states without an external clock?

A

D. Astable multivibrator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

E7A06 (A) What is a characteristic of a monostable multivibrator?

A

A. It switches momentarily to the opposite binary state and then returns to its original state after a set time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

E7A07 (D) What logical operation does a NAND gate perform?

A

D. It produces logic “0” at its output only when all inputs are logic “1”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

E7A08 (A) What logical operation does an OR gate perform?

A

A. It produces logic “1” at its output if any or all inputs are logic “1”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

E7A09 (C) What logical operation is performed by an exclusive NOR gate?

A

C. It produces logic “0” at its output if any single input is logic “1”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

E7A10 (C) What is a truth table?

A

C. A list of inputs and corresponding outputs for a digital device

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

E7A11 (D) What type of logic defines “1” as a high voltage?

A

D. Positive Logic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

E7A12 (C) What type of logic defines “0” as a high voltage?

A

C. Negative logic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

E7B01 (A) For what portion of a signal cycle does a Class AB amplifier operate?

A

A. More than 180 degrees but less than 360 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

E7B02 (A) What is a Class D amplifier?

A

A. A type of amplifier that uses switching technology to achieve high efficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

E7B03 (A) Which of the following components form the output of a class D amplifier circuit?

A

A. A low-pass filter to remove switching signal components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

E7B04 (A) Where on the load line of a Class A common emitter amplifier would bias normally be set?

A

A. Approximately half-way between saturation and cutoff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

E7B05 (C) What can be done to prevent unwanted oscillations in an RF power amplifier?

A

C. Install parasitic suppressors and/or neutralize the stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

E7B06 (B) Which of the following amplifier types reduces or eliminates even order harmonics?

A

B. Push-pull

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

E7B07 (D) Which of the following is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal?

A

D. Signal distortion and excessive bandwidth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

E7B08 (C) How can an RF power amplifier be neutralized?

A

C. By feeding a 180-degree out-of-phase portion of the output back to the input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

E7B09 (D) Which of the following describes how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a Pi-network output circuit?

A

D. The tuning capacitor is adjusted for minimum plate current, and the loading capacitor is adjusted for maximum permissible plate current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

E7B10 (B) In Figure E7-1, what is the purpose of R1 and R2?

A

B. Fixed bias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

E7B11 (D) In Figure E7-1, what is the purpose of R3?

A

D. Self bias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

E7B12 (C) What type of amplifier circuit is shown in Figure E7-1?

A

C. Common emitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

E7B13 (A) In Figure E7-2, what is the purpose of R?

A

A. Emitter load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

E7B14 (B) Why are switching amplifiers more efficient than linear amplifiers?

A

B. The power transistor is at saturation or cut off most of the time, resulting in low power dissipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

E7B15 (C) What is one way to prevent thermal runaway in a bipolar transistor amplifier?

A

C. Use a resistor in series with the emitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

E7B16 (A) What is the effect of intermodulation products in a linear power amplifier?

A

A. Transmission of spurious signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

E7B17 (A) Why are odd-order rather than even-order intermodulation distortion products of concern in linear power amplifiers?

A

A. Because they are relatively close in frequency to the desired signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

E7B18 (C) What is a characteristic of a grounded-grid amplifier?

A

C. Low input impedance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

E7C01 (D) How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network’s input and output?

A

D. A capacitor is connected between the input and ground, another capacitor is connected between the output and ground, and an inductor is connected between input and output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

E7C02 (C) Which of the following is a property of a T-network with series capacitors and a parallel shunt inductor?

A

C. It is a high-pass filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

E7C03 (A) What advantage does a Pi-L-network have over a regular Pi-network for impedance matching between the final amplifier of a vacuum-tube transmitter and an antenna?

A

A. Greater harmonic suppression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

E7C04 (C) How does an impedance-matching circuit transform a complex impedance to a resistive impedance?

A

C. It cancels the reactive part of the impedance and changes the resistive part to a desired value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

E7C05 (D) Which filter type is described as having ripple in the passband and a sharp cutoff?

A

D. A Chebyshev filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

E7C06 (C) What are the distinguishing features of an elliptical filter?

A

C. Extremely sharp cutoff with one or more notches in the stop band

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

E7C07 (B) What kind of filter would you use to attenuate an interfering carrier signal while receiving an SSB transmission?

A

B. A notch filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

E7C08 (A) Which of the following factors has the greatest effect in helping determine the bandwidth and response shape of a crystal ladder filter?

A

A. The relative frequencies of the individual crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

E7C09 (B) What is a Jones filter as used as part of an HF receiver IF stage?

A

B. A variable bandwidth crystal lattice filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

E7C10 (B) Which of the following filters would be the best choice for use in a 2 meter repeater duplexer?

A

B. A cavity filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

E7C11 (D) Which of the following is the common name for a filter network which is equivalent to two L-networks connected back-to-back with the two inductors in series and the capacitors in shunt at the input and output?

A

D. Pi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

E7C12 (B) Which describes a Pi-L-network used for matching a vacuum tube final amplifier to a 50 ohm unbalanced output?

A

B. A Pi-network with an additional series inductor on the output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

E7C13 (A) What is one advantage of a Pi-matching network over an L-matching network consisting of a single inductor and a single capacitor?

A

A. The Q of Pi-networks can be varied depending on the component values chosen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

E7C14 (C) Which mode is most affected by non-linear phase response in a receiver IF filter?

A

C. Digital

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

E7C15 (D) What is a crystal lattice filter?

A

D. A filter with narrow bandwidth and steep skirts made using quartz crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

E7D01 (D) What is one characteristic of a linear electronic voltage regulator?

A

D. The conduction of a control element is varied to maintain a constant output voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

E7D02 (C) What is one characteristic of a switching electronic voltage regulator?

A

C. The controlled device’s duty cycle is changed to produce a constant average output voltage

48
Q

E7D03 (A) What device is typically used as a stable reference voltage in a linear voltage regulator?

A

A. A Zener diode

49
Q

E7D04 (B) Which of the following types of linear voltage regulator usually make the most efficient use of the primary power source?

A

B. A series regulator

50
Q

E7D05 (D) Which of the following types of linear voltage regulator places a constant load on the unregulated voltage source?

A

D. A shunt regulator

51
Q

E7D06 (C) What is the purpose of Q1 in the circuit shown in Figure E7-3?

A

C. It increases the current-handling capability of the regulator

52
Q

E7D07 (A) What is the purpose of C2 in the circuit shown in Figure E7-3?

A

A. It bypasses hum around D1

53
Q

E7D08 (C) What type of circuit is shown in Figure E7-3?

A

C. Linear voltage regulator

54
Q

E7D09 (C) What is the main reason to use a charge controller with a solar power system?

A

C. Prevention of battery damage due to overcharge

55
Q

E7D10 (C) What is the primary reason that a high-frequency switching type high voltage power supply can be both less expensive and lighter in weight than a conventional power supply?

A

C. The high frequency inverter design uses much smaller transformers and filter components for an equivalent power output

56
Q

E7D11 (D) What circuit element is controlled by a series analog voltage regulator to maintain a constant output voltage?

A

D. Pass transistor

57
Q

E7D12 (C) What is the drop-out voltage of an analog voltage regulator?

A

C. Minimum input-to-output voltage required to maintain regulation

58
Q

E7D13 (C) What is the equation for calculating power dissipation by a series connected linear voltage regulator?

A

C. Voltage difference from input to output multiplied by output current

59
Q

E7D14 (C) What is one purpose of a “bleeder” resistor in a conventional unregulated power supply?

A

C. To improve output voltage regulation

60
Q

E7D15 (D) What is the purpose of a “step-start” circuit in a high voltage power supply?

A

D. To allow the filter capacitors to charge gradually

61
Q

E7D16 (D) When several electrolytic filter capacitors are connected in series to increase the operating voltage of a power supply filter circuit, why should resistors be connected across each capacitor?

A

A. To equalize, as much as possible, the voltage drop across each capacitor B. To provide a safety bleeder to discharge the capacitors when the supply is off C. To provide a minimum load current to reduce voltage excursions at light loads D. All of these choices are correct

62
Q

E7E01 (B) Which of the following can be used to generate FM phone emissions?

A

B. A reactance modulator on the oscillator

63
Q

E7E02 (D) What is the function of a reactance modulator?

A

D. To produce PM signals by using an electrically variable inductance or capacitance

64
Q

E7E03 (C) How does an analog phase modulator function?

A

C. By varying the tuning of an amplifier tank circuit to produce PM signals

65
Q

E7E04 (A) What is one way a single-sideband phone signal can be generated?

A

A. By using a balanced modulator followed by a filter

66
Q

E7E05 (D) What circuit is added to an FM transmitter to boost the higher audio frequencies?

A

D. A pre-emphasis network

67
Q

E7E06 (A) Why is de-emphasis commonly used in FM communications receivers?

A

A. For compatibility with transmitters using phase modulation

68
Q

E7E07 (B) What is meant by the term baseband in radio communications?

A

B. The frequency components present in the modulating signal

69
Q

E7E08 (C) What are the principal frequencies that appear at the output of a mixer circuit?

A

C. The two input frequencies along with their sum and difference frequencies

70
Q

E7E09 (A) What occurs when an excessive amount of signal energy reaches a mixer circuit?

A

A. Spurious mixer products are generated

71
Q

E7E10 (A) How does a diode detector function?

A

A. By rectification and filtering of RF signals

72
Q

E7E11 (C) Which type of detector is used for demodulating SSB signals?

A

C. Product detector

73
Q

E7E12 (D) What is a frequency discriminator stage in a FM receiver?

A

D. A circuit for detecting FM signals

74
Q

E7F01 (C) What is meant by direct digital conversion as applied to software defined radios?

A

C. Incoming RF is digitized by an analog-to-digital converter without being mixed with a local oscillator signal

75
Q

E7F02 (A) What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?

A

A. An adaptive filter

76
Q

E7F03 (C) What type of digital signal processing filter is used to generate an SSB signal?

A

C. A Hilbert-transform filter

77
Q

E7F04 (D) What is a common method of generating an SSB signal using digital signal processing?

A

D. Combine signals with a quadrature phase relationship

78
Q

E7F05 (B) How frequently must an analog signal be sampled by an analog-to-digital converter so that the signal can be accurately reproduced?

A

B. At twice the rate of the highest frequency component of the signal

79
Q

E7F06 (D) What is the minimum number of bits required for an analog-to-digital converter to sample a signal with a range of 1 volt at a resolution of 1 millivolt?

A

D. 10 bits

80
Q

E7F07 (C) What function can a Fast Fourier Transform perform?

A

C. Converting digital signals from the time domain to the frequency domain

81
Q

E7F08 (B) What is the function of decimation with regard to digital filters?

A

B. Reducing the effective sample rate by removing samples

82
Q

E7F09 (A) Why is an anti-aliasing digital filter required in a digital decimator?

A

A. It removes high-frequency signal components which would otherwise be reproduced as lower frequency components

83
Q

E7F10 (A) What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a Direct Digital Conversion SDR?

A

A. Sample rate

84
Q

E7F11 (B) What sets the minimum detectable signal level for an SDR in the absence of atmospheric or thermal noise?

A

B. Reference voltage level and sample width in bits

85
Q

E7F12 (A) What digital process is applied to I and Q signals in order to recover the baseband modulation information?

A

A. Fast Fourier Transform

86
Q

E7F13 (D) What is the function of taps in a digital signal processing filter?

A

D. Provide incremental signal delays for filter algorithms

87
Q

E7F14 (B) Which of the following would allow a digital signal processing filter to create a sharper filter response?

A

B. More taps

88
Q

E7F15 (A) Which of the following is an advantage of a Finite Impulse Response (FIR) filter vs an Infinite Impulse Response (IIR) digital filter?

A

A. FIR filters delay all frequency components of the signal by the same amount

89
Q

E7F16 (D) How might the sampling rate of an existing digital signal be adjusted by a factor of 3/4?

A

D. Interpolate by a factor of three, then decimate by a factor of four

90
Q

E7F17 (D) What do the letters I and Q in I/Q Modulation represent?

A

D. In-phase and Quadrature

91
Q

E7G01 (A) What is the typical output impedance of an integrated circuit op-amp?

A

A. Very low

92
Q

E7G02 (D) What is the effect of ringing in a filter?

A

D. Undesired oscillations added to the desired signal

93
Q

E7G03 (D) What is the typical input impedance of an integrated circuit op-amp?

A

D. Very high

94
Q

E7G04 (C) What is meant by the term op-amp input offset voltage?`

A

C. The differential input voltage needed to bring the open loop output voltage to zero

95
Q

E7G05 (A) How can unwanted ringing and audio instability be prevented in a multi-section op-amp RC audio filter circuit?

A

A. Restrict both gain and Q

96
Q

E7G06 (D) Which of the following is the most appropriate use of an op-amp active filter?

A

D. As an audio filter in a receiver

97
Q

E7G07 (C) What magnitude of voltage gain can be expected from the circuit in Figure E7-4 when R1 is 10 ohms and RF is 470 ohms?

A

C. 47

98
Q

E7G08 (D) How does the gain of an ideal operational amplifier vary with frequency?

A

D. It does not vary with frequency

99
Q

E7G09 (D) What will be the output voltage of the circuit shown in Figure E7-4 if R1 is 1000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?

A

D. -2.3 volts

100
Q

E7G10 (C) What absolute voltage gain can be expected from the circuit in Figure E7-4 when R1 is 1800 ohms and RF is 68 kilohms?

A

C. 38

101
Q

E7G11 (B) What absolute voltage gain can be expected from the circuit in Figure E7-4 when R1 is 3300 ohms and RF is 47 kilohms?

A

B. 14

102
Q

E7G12 (A) What is an integrated circuit operational amplifier?

A

A. A high-gain, direct-coupled differential amplifier with very high input impedance and very low output impedance

103
Q

E7H01 (D) What are three oscillator circuits used in Amateur Radio equipment?

A

D. Colpitts, Hartley and Pierce

104
Q

E7H02 (C) Which describes a microphonic?

A

C. Changes in oscillator frequency due to mechanical vibration

105
Q

E7H03 (A) How is positive feedback supplied in a Hartley oscillator?

A

A. Through a tapped coil

106
Q

E7H04 (C) How is positive feedback supplied in a Colpitts oscillator?

A

C. Through a capacitive divider

107
Q

E7H05 (D) How is positive feedback supplied in a Pierce oscillator?

A

D. Through a quartz crystal

108
Q

E7H06 (B) Which of the following oscillator circuits are commonly used in VFOs?

A

B. Colpitts and Hartley

109
Q

E7H07 (D) How can an oscillator’s microphonic responses be reduced?

A

D. Mechanically isolating the oscillator circuitry from its enclosure

110
Q

E7H08 (A) Which of the following components can be used to reduce thermal drift in crystal oscillators?

A

A. NP0 capacitors

111
Q

E7H09 (A) What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?

A

A. A direct digital synthesizer

112
Q

E7H10 (B) What information is contained in the lookup table of a direct digital frequency synthesizer?

A

B. The amplitude values that represent a sine-wave output

113
Q

E7H11 (C) What are the major spectral impurity components of direct digital synthesizers?

A

C. Spurious signals at discrete frequencies

114
Q

E7H12 (B) Which of the following must be done to insure that a crystal oscillator provides the frequency specified by the crystal manufacturer?

A

B. Provide the crystal with a specified parallel capacitance

115
Q

E7H13 (D) Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?

A

A. Use a GPS signal reference B. Use a rubidium stabilized reference oscillator C. Use a temperature-controlled high Q dielectric resonator D. All of these choices are correct

116
Q

E7H14 (C) What is a phase-locked loop circuit?

A

C. An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator

117
Q

E7H15 (D) Which of these functions can be performed by a phase-locked loop?

A

D. Frequency synthesis, FM demodulation

Ham Extra 2016-2020 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions