Correct Answer - Option 4 : Electromagnetic
Ammeters and voltmeters are classified as follows:
1. Moving Coil instruments:
- Permanent magnet type
- Dynamometer type
2. Moving Iron Type instruments:
- Attraction type
- Repulsion type
3. Hotwire instrument
4. Induction type instrument
5. Electrostatic instrument(voltmeter only)
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Permanent Magnet Moving Coil (PMMC) is only used for DC measurements.
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Moving Iron (MI) type instruments can be used for both AC & DC measurements.
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Rectifier-type instruments are used for both AC & DC measurements.
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Induction-type instruments are only used for AC measurements.
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Hotwire instruments can be used for both DC as well as AC quantities.
