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AT1 > Test Equipment (2018) > Flashcards

Test Equipment (2018) Flashcards

1
Q

Name one of the chief causes of test set failure.

A

Carelessness

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2
Q

Although test equipment is repaired at the intermediate-level maintenance activity, most work performed at this level on test equipment consists of

A

Calibration

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3
Q

What is the most delicate part of a piece of test equipment?

A

Meters

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4
Q

List the basic measuring parameters of electronic equipment.

A 
Voltage
Current
Resistance
Power
Frequency
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5
Q

What is the most accurate portion of the ohmmeter scale, and why?

A

The midscale portion of the scale represents the most accurate area because the ohms-calibrated scale is nonlinear

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6
Q

When repairing equipment, you should use a meter with the same sensitivity as specified in schematics and wiring diagrams. What is the reason for doing this?

A

Because of circuit loading, you should use a meter with the same sensitivity to obtain accurate readings.

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7
Q

Name the piece of test equipment that consists of a hand-driven dc genera- tor, applies a high voltage to the com- ponent under test, and measures current leakage.

A

megohmmeter or megger

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8
Q

Loading effect is the result of a meter’s sensitivity, and it causes incorrect voltage indications. What relationship exists between a meter’s sensitivity and its loading effect?

A

the lower the sensitivity of the meter, the greater the loading effect.

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9
Q

What is the major difference between a VTVM and a conventional multimeter?

A

the VTVM uses a vacuum tube in its input

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10
Q

A phase angle voltmeter is used to determine the overall accuracy of electronic equipment by measuring phase angles. What is actually measured by the phase angle voltmeter?

A

A phase measuring device must measure the phase difference between 2 discrete frequencies, regardless of the phase and amplitude to other components of the waveform.

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11
Q

Describe the general function of a differential voltmeter.

A

Its general function is to compare an unknown voltage with an internal reference voltage and to indicate the difference in their values

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12
Q

What item of test equipment is used to indicate the frequency of an external signal?

A

Frequency meter.

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13
Q

List the parts of most heterodyne frequency meters.

A

A heterodyne oscillator, RF harmonic amplifier, crystal-controlled oscillator , a mixer or detector , a modulator , an AF output amplifier, and a means for indicating frequency.

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14
Q

Wavemeters are calibrated resonant circuits used to measure frequency. List the three basic kinds of wavemeters.

A

Absorption, reaction, and transmission.

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15
Q

Of the three basic wavemeters, which one is commonly used to measure microwave frequencies?

A

Transmission.

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16
Q

The counter frequency meter is a high-speed electronic counter, with an accurate, crystal- controlled time base. What does this combination provide?

A

A frequency meter that automatically counts and displays the number of events (hertz) occurring in a precise interval.

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17
Q

What does the Model 5245L counter frequency meter measure?

A

Frequency, period average, ratio of two frequencies, and total events.

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18
Q

By what method is dc power determined?

A

P = IE

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19
Q

You use a resistor that is specially designed to dissipate the required amount of power and replace normal loads. List the two types of resistors used for this purpose.

A

dummy loads

dummy antennas

20
Q

List the major sources of error that affect the overall accuracy of power measurements.

A

mismatch error
RF losses
instrumentation error

21
Q

The Huntron Trackers 1000 and 2000 are for use on circuit boards and systems with all voltage sources in what condition?

A

in the power off condition

22
Q

What mode on the automatic transistor analyzer Model 900 has the SonalertTM?

A

the SND mode

23
Q

What type signal display does the Huntron

Trackers 1000 and 2000 show when the signal fuse is open and the test leads shorted together?

A

displays short circuit signatures, even with the test leads open

24
Q

When using the Huntron Tracker 2000, why must you make good contact with the test leads?

A

because the test leads are conductive only at the tips.

25
Q

What is the minimum total shunt im- pedance across the junction of the diode or transistor under test using the automatic transistor analyzer Model 900 to ensure a good test reading?

A

not less than 270 ohms

26
Q

What is the principal function of the signal generator?

A

the production of an alternating voltage of the desired frequency and amplitude

27
Q

While various types of FM signal generators are available, many are restricted to special applications. What type is used for general applications?

A

the sweep generator

28
Q

Most frequency-swept signal generators use a reactance-tube method of modulation. What is the reason for this?

A

it results in greater flexibility, and the equipment is light and more compact.

29
Q

What is a common application for pulse- modulated generators?

A

checking receiver performance in radar systems that have a pulse-type emission

30
Q

Signal analyzers can be used in many applications. It is used for what function?

A

to check the response of an equipment under simulated conditions or specific operations

31
Q

What determination can you make by observing the square wave response?

A

whether the transmission of low or high frequencies is affected.

32
Q

An oscilloscope probe reduces the loading effect of the O-scope input circuit on the circuit under test. What is the second purpose of the probe?

A

to reduce the amount of signal voltage applied directly to the O-scope input connection

33
Q

The synchroscope is an adaption of the

oscilloscope. What is the difference of the trace on the synchroscope and oscilloscope?

A

a trace on the synchroscope is produced only when it is initiated by an input trigger; the O-scope has a continuous sawtooth sweep.

34
Q

Describe what factors a spectrum analyzer exhibits.

A

a spectrum analyzer is a device for exhibiting the spectrum of modulated waves in the radio-frequency range and microwave region

35
Q

Describe the purpose of the echo box.

A

it is used in field testing, troubleshooting and adjusting pulsed -type radar systems.

36
Q

What limitation should you consider when you use the echo box?

A

you need to remember that the echo box presents only relative rather than absolute values of power and sensitivity and only rough values of frequency.

37
Q

Describe some of the main uses for the TDR.

A

test sets are used to check and troubleshoot aircraft wiring, transmission lines, and antenna systems for shorts, opens, crimps, or bad couplings

38
Q

Describe the basics of TDR.

A

begins with the insertion of a step of pulse of energy into a system of cable. then, at the point of insertion, the energy reflected is observed.

39
Q

While you can determine different types of discontinuities with the TDR, what else can
you determine through proper analysis?

A

you can determine if the discontinuity is resistive, inductive, or capacitive and whether it is in series or parallel with the load

40
Q

What factor determines the speed at which a wave travels through a transmission system?

A

the systems velocity constant; a wave travels through air faster than it does through polyethylene

41
Q

By what method does using a TDR help you locate an unacceptable connector?

A

TDR rapidly shows where mismatches are located; how bad they are; if they are resistive, capacitive, or inductive; and whether in series or shunt.

42
Q

While TDR and FDR provide similar measurements, the FDR eliminates what limitation of the TDR?

A

FDR checks cables at their actual operating frequencies, eliminating the limitation of TDR discontinuities outside the operating frequencies

43
Q

Describe the means by which the FDR identifies defective systems.

A

the FDR identifies defective systems by injecting an RF signal into a system and using insertion loss and return loss measurements to classify the system under these as good or in need of repair.

44
Q

When determining cable lengths or distance to faults, what means do you use to determine the number of feet from the cable end to the fault?

A

the resulting CRT display consists of a series of half-dome ripples. a count of the total number of these ripples multiplied by the calibration factor identifies the location of the fault

45
Q

List the elements of a typical VAST station.

A

a computer subsystem, a data transfer unit, and a stimulus and measurement section that contains functional building blocks configured to meet the intended test applications

46
Q

List the three levels of detection that ensure rapid confidence tests and easy fault detection.

A

auto-check
self-check
self-test

47
Q

What is the purpose of programmed halts?

A

to allow manual intervention during the course of testing to make adjustments and observations.

AT1 (31 decks)

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