6 Different Types of Ammeter and Voltmeter | Their Uses

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In this article, we are going to study what are the different types of ammeter and voltmeter.

Before, I have explained the difference between ammeter and voltmeter with the all basic concepts. Both instruments are very crucial in electrical measurement and instrumentation.

For measuring and operating the electrical quantities (i.e. current or voltage or energy or power), the ammeter and voltmeter have an integral role. As per the measure of different aspects of electricity, various types of ammeter and voltmeter are used in the electric circuits.

Here is a listing of the different types of ammeter and voltmeter one-by-one.

Classification of Ammeter and Voltmeter

Based on the construction and working function, the ammeter and voltmeter are classified into the following parts.

1. Moving Iron Instrument

The moving iron (MI) type instrument is worked as an indicating instrument. This instrument accurately measures the alternating current (AC) or direct current (DC).

The construction of moving iron is very simple and robust. And it is cheaper in cost as compared to the other instruments.

There are two basic types of such instruments as follow.

  • Attraction type instrument
  • Repulsion type instrument

This type of instrument is widely used in commercial uses such as in laboratories and switchboards.

2. Moving Coil Instrument

The moving coil is an accurate type of instrument which is widely used for the DC measurements of voltage, current, and resistance.

There are two types of moving coil instruments as given.

  • Permanent magnetic moving coil (PMMC) instrument
  • Dynamometer type moving coil instrument

The PMMC is a very accurate type. It is mainly used for DC measurements (current and voltage only).

But, the dynamometer is useful for both AC as well as DC measurements (such as current, voltage, and power). So, this instrument is very essential as a ‘Transfer instrument‘ or ‘Standard instrument‘.

3. Thermal Instrument

The thermal instrument has the same calibration for the alternating current and direct current. This type of instrument is mostly used in the heating effect of the electric current.

Mainly, there are two types of thermal instruments like as-

  • Hot-wire type instrument
  • Thermocouple type instrument

The hot-wire instrument is used for the AC as well as DC calibration. It has a simple construction and more accuracy in measurement. The cost of this instrument is low.

The thermocouple instrument works as a temperature sensor. It is basically used for the AC or DC measurements (current and voltage). It is useful as a transfer instrument for calibration of measurement.

4. Electrostatic Instrument

The electrostatic instrument is a type of voltmeter which is used to measure the alternating as well as direct voltage. Also, it has the capability to measure the potential difference.

It works based on the existence of electric force between the charged objects or plates.

Based on the construction and measuring capabilities, there are three types of electrostatic voltmeters.

  • Attracted disc type voltmeter
  • Quadrant type voltmeter
  • Multicellular type voltmeter

An attracted disc type voltmeter is suitable for the measurement of high voltage (above 20 kV). The quadrant type voltameter is suitable for the measurement of low voltage (up to 20 kV).

And multicellular type voltmeter is very sensitive over the quadrant type. It is used to measure the accurately low voltage (below the 30V).

Note: The electrostatic instrument can not be used as an Ammeter.

5. Induction Instrument

The induction instrument is suitable only for the AC measurement (i.e. current, voltage, power, and energy). Thus, it can be worked as an ammeter or voltmeter or wattmeter, or energy meter.

This instrument is working based on the induction motor principle. It has two different types.

  • Shaded-pole type
  • Split-phase type

This instrument is worked for the measurement of single-phase AC.

6. Rectifier Instrument

The rectifier instrument is used for the measurement of the audio frequency of alternating current or voltage.

This type of instrument is very essential in communication circuits. Because, it has high sensitivity and low power consumption.

The above 6 different types of ammeter and voltmeter are covered. In an upcoming article, I will explain each instrument with its advantages and disadvantages.

If you have any queries or points to ask regarding ammeter and voltmeter types, write in the given comment.

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