LESSON 5
DIFFERENTIAL VOLTMETER MODEL 887AB/AN
TASK
Describe and identify theory, terminology, and operation of Differential
Voltmeter Model 887AB/AN.
CONDITIONS
Given information and illustrations about theory, terminology, and operation
of Differential Voltmeter Model 887AB/AN.
STANDARDS
Demonstrate competency of the task skills and knowledge by correctly
responding to 80 percent of the multiple-choice test covering Differential
Voltmeter Model 887AB/AN.
REFERENCES
Technical manual for Fluke Model 887AB/AN Differential Voltmeter.
Learning Event 1:
DESCRIBE THE DIFFERENTIAL VOLTMETER
1.
Among the most accurate and reliable measuring devices you will
encounter are the differential voltmeters. The high accuracy, portability,
and compactness of the differential voltmeter make this instrument ideal for
precise measurement of almost any ac or dc voltage.
Ease of operation,
inherent protection from accidental overload, and high reliability
contribute to the outstanding performance that assures stability for both
production-line testing and laboratory measurement.
This instrument is
capable of being used as a voltmeter, as a precision potentiometer, and as a
megohmmeter for measurement of high resistance.
It can also be used to
measure the excursions of a voltage about some nominal value.
2.
Some of the advantages of differential voltmeters are:
circuit
loading is negligible, error due to meter reading interpolation is
eliminated, error due to parallax is reduced, and ease of operation.
3.
The big disadvantage of all passive-type meters is their loading
effect.
In Figure 5-1, a 1000-ohm-per-volt voltmeter with an accuracy of
0.1 percent is used to measure 10 Vdc across a 10-kilohm resistor.
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