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56 Cards in this Set
- Front
- Back
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What is one of the greatest advantages of a VOM?
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No external power source is required.
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Before you connect a VOM in a circuit for an ohmmeter reading, in what condition must the
circuit be? |
De-energized.
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When taking resistance readings with a VOM, you will obtain the most accurate readings at or
near what part of the scale? |
Midscale.
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Besides setting up the meter for expected voltage ranges, what must be strictly observed when
taking dc voltage readings? |
Polarity
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Power for the electronic digital multimeter is normally supplied by what internal power source?
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Rechargeable batteries
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How is an overload condition indicated by the electronic digital multimeter?
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Simultaneous flashing of display readouts
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In an electronic digital multimeter, the digital information is displayed by what type of numerical
readouts? |
Light-emitting diodes.
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What is the general function of the differential voltmeter?
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To compare an unknown voltage with a known reference voltage and indicate the difference in
their values. |
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What element controls the number of electrons striking the screen?
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Control grid.
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What element is controlled to focus the beam?
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The first anode
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Why are the electrostatic fields between the electron gun elements called lenses
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Because they bend electron streams in much the same manner that optical lenses bend light rays.
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What is the function of the second anode
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It accelerates the electrons emerging from the first anode.
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What effect do longer deflection plates have on the electron beam?
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A greater deflection angle.
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What effect does closer spacing of plates have on the electron beam?
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A greater deflection angle.
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Is the deflection angle greater with higher or lower potential on the plates?
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Higher potential
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Is the deflection angle greater when the beam is moving faster or slower?
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Slower beam.
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Waveforms are described in terms of what two functions?
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Amplitude and time.
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The vertical-deflection plates are used to reproduce what function?
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Amplitude.
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The horizontal-deflection plates are used to produce what function?
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Time and/or frequency relationships
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Why are the ends of the deflection plates bent outward?
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To permit wide-angle deflection of the beam
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What term is used to describe the reciprocal of deflection sensitivity of a scope?
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Deflection factor
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List the circuits that all oscilloscopes have in common
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A CRT, a group of control circuits, power supply, sweep circuitry, and deflection circuitry.
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When you select the time base to display a signal, should the time base be the same, higher, or
lower than the input signal? |
Lower.
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Oscilloscopes are used to measure what quantities?
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Amplitude, phase, time, and frequency.
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Scopes that produce two channels on a single CRT with a single beam are referred to as what
types of scopes? |
Dual-trace oscilloscopes.
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The first converter is also known by what other name?
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Front end.
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What is the logarithmic ratio between the input and output of a given circuit called?
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Bel.
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What term is used to represent power levels above or below a 1-milliwatt reference?
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dBm.
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What milliwatt value is equal to +6 dBm?
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4 mW.
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What name is given to a resistor used to replace the normal load in a circuit?
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Dummy load or dummy antenna
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What are the two types of bolometers?
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Barretter and thermistor
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As the dissipated power increases, what effect does this have on the resistance of a thermistor?
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It increases.
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In a heterodyne-type frequency meter, what is the difference between the oscillator frequency and
the unknown frequency? |
Beat frequency.
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What equipment uses a calibrated resonant circuit to measure frequency?
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Wavemeter.
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Name two instruments used to analyze waveforms.
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Oscilloscope and spectrum analyzer.
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What device sweeps a band of frequencies to determine frequencies and amplitudes of each
frequency component? |
Spectrum analyzer.
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What is the typical back-to-forward resistance ratio of a good-quality diode?
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10-to-1 ratio.
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As a transistor ages, what happens to the leakage current?
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It tends to increase.
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What element controls the number of electrons striking the screen?
|
Control grid.
|
|
|
What element is controlled to focus the beam?
|
The first anode.
|
|
|
Why are the electrostatic fields between the electron gun elements called lenses?
|
Because they bend electron streams in much the same manner that optical lenses bend light rays.
|
|
|
What is the function of the second anode?
|
It accelerates the electrons emerging from the first anode.
|
|
|
What effect do longer deflection plates have on the electron beam?
|
A greater deflection angle
|
|
|
What effect does closer spacing of plates have on the electron beam?
|
A greater deflection angle.
|
|
|
Is the deflection angle greater with higher or lower potential on the plates?
|
Higher potential.
|
|
|
Is the deflection angle greater when the beam is moving faster or slower?
|
Slower beam.
|
|
|
Waveforms are described in terms of what two functions?
|
Amplitude and time.
|
|
|
The vertical-deflection plates are used to reproduce what function?
|
Amplitude
|
|
|
The horizontal-deflection plates are used to produce what function?
|
Time and/or frequency relationships
|
|
|
Why are the ends of the deflection plates bent outward?
|
To permit wide-angle deflection of the beam.
|
|
|
What term is used to describe the reciprocal of deflection sensitivity of a scope?
|
Deflection factor.
|
|
|
List the circuits that all oscilloscopes have in common
|
A CRT, a group of control circuits, power supply, sweep circuitry, and deflection circuitry.
|
|
|
When you select the time base to display a signal, should the time base be the same, higher, or
lower than the input signal? |
Lower
|
|
|
Oscilloscopes are used to measure what quantities?
|
Amplitude, phase, time, and frequency.
|
|
|
Scopes that produce two channels on a single CRT with a single beam are referred to as what
types of scopes? |
Dual-trace oscilloscopes
|
|
|
The first converter is also known by what other name?
|
Front end
|
