Electrical Measuring Instruments
Course Number: 724.1
The Electrical Measuring Instruments textbook covers the principles on which electrical test instruments operate. Basic instruments covered include voltmeter, ammeter, watt meter, ohmmeter, and meg ohmmeter. Covers AC metering, split-core ammeter, use of current and potential transformers. Includes detailed coverage of modern multimeter. Explains functions and uses of oscilloscopes.
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to include topics lists, objectives, & key terms for every chapter.
Recommended Contact Hours – 8
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Table of Contents
Chapter 1: Principles of Meter Operation
Topics: Digital meter design; Integrated ADCs; Displays; Introduction to analog meters; D'Arsonval movement; Magnetic shielding; Parallax error; Accuracy
- Define the terms digital meter and analog meter.
- Describe the purpose of the analog-to-digital converter in a digital meter.
- Identify and label graphs of integrator output from a dual-slope integrating meter.
- Explain how time is related to voltage measurement in an integrating digital meter.
- Differentiate among the terms accuracy, sensitivity, and resolution.
- Explain how a D'Arsonval meter movement works.
- Describe the parallax effect, and explain how to avoid it when using an analog meter.
- State the sensitivity formula for an analog meter.
Chapter 2: Ammeters, Voltmeters, and Wattmeters
Topics: Measurement considerations; Measuring direct current; Multirange ammeters; Measuring alternating current; Voltmeters; Wattmeters
- Describe the differences and similarities between an analog ammeter and a voltmeter.
- Explain how ammeters and voltmeters are protected internally from overcurrent.
- Explain how a make-then-break switch works.
- Identify which meters should be connected in series in a circuit and which should be connected in parallel.
- Describe how an analog wattmeter works.
- Explain how it is possible to overload a wattmeter, even with the meter's pointer at less than full-scale deflection.
Chapter 3: Resistance Measurement
Topics: Measuring resistance with an ohmmeter; Checking and calibrating an ohmmeter; Shunt ohmmeters; Megohmmeters
- characteristic differences between a series ohmmeter and a shunt ohmmeter.
- Explain why ohmmeter scales read from right to left, instead of left to right, and why they are nonlinear.
- Describe the internal circuits and basic operation of an opposed-coil megohmmeter.
- State the primary safety precaution to take when using an ohmmeter.
- Describe two methods used by ohmmeter manufacturers to extend the range of their instruments.
- Explain how to test for opens, shorts, and grounds, using a megohmmeter.
- Describe how to make zero-adjustments on ohmmeters and megohmmeters.
- Explain why variable resistors are needed in battery-powered ohmmeters.
Chapter 4: Multimeters
Topics: Graphical DMM; Advanced meter functions; Multimeter accessories and safety
- Demonstrate how to measure ac and dc current and voltage with a multimeter.
- Describe the function of a current probe.
- Explain how to isolate the source of a glitch with a graphical multimeter.
- Demonstrate how to read the screen display of a graphical multimeter in the Trend mode.
- Explain why you set a meter to its highest range before taking your first measurement.
- Define autoranging and auto-polarity.
- List three safety precautions to take when using multimeters.
Chapter 5: Oscilloscopes
Topics: Kinds of oscilloscopes; Triggering; Digital oscilloscopes; Dual-trace oscilloscopes; Controls; Probes; Oscilloscopes in troubleshooting
- Describe how an analog oscilloscope works.
- Describe advantages of a digital oscilloscope over an analog oscilloscope.
- Demonstrate how to measure voltage with an oscilloscope.
- Show two methods of determining phase angles with an oscilloscope.
Add Chapters to Your Custom Book
- Chapter 1: Principles of Meter Operation
- Chapter 2: Ammeters, Voltmeters, and Wattmeters
- Chapter 3: Resistance Measurement
- Chapter 4: Multimeters
- Chapter 5: Oscilloscopes
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