Chapter TwoVoltage and Current Measurement

CONTINUE

بسم الله الرحمن الرحيم

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2.4. Current Measurement

Current measuring devices are selected for: Precision Stability Frequency response, including dc Galvanic isolation بعدم التام العزل من التأكد

تيار مرور 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

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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