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Subelement A

Principles

Section 6

Electrical Measurements

An AC ammeter indicates:

  • Effective (TRM) values of current.
  • Correct Answer
    Effective (RMS) values of current.
  • Peak values of current.
  • Average values of current.

An AC ammeter indicates:

Effective (RMS) values of current.

For more info, please see Test Guy site for the article on RMS Voltage Tutorial and the article on Peak vs. Average vs. RMS Voltage

Also see All About Circuits site for the article on AC Voltmeters and Ammeters

And, see YouTube video from Simply Info channel, called What is Ammeter

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By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak voltage value?

  • 0.707
  • 0.9
  • Correct Answer
    1.414
  • 3.14

By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak voltage value?

1.414

For more info, please see Wikipedia's article on Square root of 2. It's application to the electronics lies in the use of the calculation method.

For application of 1.414 in electronics, please see Electrical4U, article on RMS Voltage: What it is? (Formula And How To Calculate It), section Peak Voltage From RMS Voltage

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What is the RMS voltage at a common household electrical power outlet?

  • 331-V AC.
  • 82.7-V AC.
  • 165.5-V AC.
  • Correct Answer
    117-V AC.

What is the RMS voltage at a common household electrical power outlet?

117-V AC.

For more info, please see Wikipedia's article on Mains electricity

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What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?

  • Correct Answer
    Peak-to-peak.
  • RMS.
  • Average.
  • DC.

What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?

Peak-to-peak.

Looking at sine wave, it is easy to see peaks of waves. The peak is the maximum voltage in each cycle of AC current. Then, it is easy to measure from one peak to another.

Also, looking at the bottom of sine wave cycle, you can measure the negative peaks.

For more info, please see the Electronics Stack Exchange site, for the article on Peak to Peak vs. Amplitude

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By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?

  • 0.707
  • 1.414
  • Correct Answer
    0.9
  • 3.14

By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the average voltage value?

0.9

For more info, please see Electronics Tutorials article on Average Voltage Tutorial

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What is the peak voltage at a common household electrical outlet?

  • 234 volts.
  • 117 volts.
  • 331 volts.
  • Correct Answer
    165.5 volts.

What is the peak voltage at a common household electrical outlet?

165.5 volts.

From wp2ahg:

Household voltage is 117 volts RMS.

To convert from RMS to peak voltage, multiply by 1.414.

117 volts X 1.414 = 165.5 volts


For more info, please see Test Guy site for the article on Peak vs. Average vs. RMS Voltage

Reference 2: AC Circuit Theory (Part 3): Peak, Average, and RMS Values

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