Download Chapter Two Voltage and Current Measurement

‫بسم هللا الرحمن الرحيم‬
Chapter Two
Voltage and Current Measurement
CONTINUE
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2.4. Current Measurement
Current measuring devices are selected for:
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Precision
Stability
Frequency response, including dc
Galvanic isolation ‫التأكد من العزل التام بعدم مرور تيار‬
Presentation of the data
Effect on measured circuit
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Using an Ammeter as a Voltmeter
and vice versa
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Using a Voltmeter as an Ammeter
By using a shunt
resistance to
reduce the large
internal resistance
of the voltmeter,
so that it can be
connected in series
in the circuit
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Using an Ammeter as a Voltmeter
By using a series
resistance to
enlarge the small
internal resistance
of the ammeter ,
so that it can be
connected in
parallel in the
circuit
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Figure 2.34 Changing the range of a Voltmeter using a
number of high resistance resistors connected in series
with meter coil and known as multiplier
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Figure 2.35 Changing the range of a Ammeter using a
number of low resistance resistors connected in parallel
with meter operating coil and known as multiplier
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Solution
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Solution
guide
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2.4.2. The Moving Magnet Meter
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2.4.3. The D’Arsonval Meter
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2.4.4. The Electrodynamometer
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2.4.5. The RF Ammeter and True rms
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2.4.6. The Current Transformer
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Current and potential transformers for
High voltage measurements
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