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Difference between Galvanometer and Ammeter

Science is a broad subject highlighting various key subjects like inertia, gravity, electric current, the human system, chemical formulas, etc. Science is not only limited to textbooks but is also used in our daily lives. Science is used in every field. For instance, many equipments and technologies are used to predict the natural calamities that can harm people. There are also certain technologies through which the damage done through calamities can also be measured.

So today, we will be talking about physics. Physics includes many topics like gravity, electricity, electric currents, etc. So, today we will discuss about electric currents and the ways one can measure them. There are two instruments with which we can measure these electric currents, i.e., galvanometer and ammeter. Well, there are certain differences between them, but let us start with their primary definitions.

Galvanometer vs Ammeter


A galvanometer is defined as an electromechanical instrument that is used for measuring electric currents. The small amounts of current are measured through a galvanometer. A galvanometer can be considered as an actuator. Now, what is an actuator? Well, an actuator is responsible for moving and controlling a specific system. The galvanometer was invented by Luigi Galvani and was first observed/ discovered by Hans Christian Orsted in 1820. Modern-day galvanometers are used for controlling and positioning the systems. Galvanometers are divided into two kinds, i.e., closed-loop and open-loop galvanometers. Apart from these two kinds, there are four types of galvanometers, namely tangent galvanometers, astatic galvanometers, mirror galvanometers, and ballistic galvanometers.

In earlier times, galvanometers were used for finding discrepancies in telecommunication cables. Galvanometers function on one basic principle, i.e., the coil having a current in the magnetic field experiences a rotation or a force. One of the major advantages of a galvanometer is that it carries a very high sensitivity. The accuracy and flexibility are also high, and it is not affected by the magnetic fields. One of the prominent disadvantages of a galvanometer is that overload can spoil it. The force or rotation in a current cannot be changed easily. The temperature change can cause the electric current to change its rotation or increase/ decrease its force. It is interesting to note that the galvanometer does not depict any quantity, i.e., there is no least count of a galvanometer. The range of the galvanometer is 500ohm.


An ammeter is defined as an instrument that is used for measuring a wide range of currents. Direct and alternative electric current is measured through an ammeter. Now, how does an ammeter work? Well, an ammeter is used to measure an electric current through a set of coils having low resistance and inductive reactance. There are several types of ammeter depending upon the construction and the measurement of current. The unit used for measuring the current in the ammeter is amperes. There are seven significant types of an ammeter. They are:

  • Moving Coil Ammeter
  • Electro-dynamic Ammeter
  • Moving Magnet Ammeter
  • Moving Iron Ammeter
  • Hot Wire Ammeter
  • Digital Ammeter
  • Integrating Ammeter

The range of an ammeter is 0-3 ampere, including thirty divisions. The formula for measuring a current through an ammeter is V=IR. In this formula, R is the resistance, I is the current flowing, and V is the difference between the two. An advantage of an ammeter is that it is portable as well as strong. It can be used in both Ac and Dc measurements, and it does not depend upon the magnetic field of the earth. One of the major disadvantages of an ammeter is that it is cannot store data. Now, there are several differences between an ammeter and a galvanometer. So, let us have a look at them.

1. A galvanometer is defined as an electromagnetic instrument that is used for measuring electric currents. On the other hand, an ammeter is an instrument used for measuring a wide range of currents.
2. There are four types of galvanometers. They are:
  • Tangent Galvanometer
  • Astatic Galvanometer
  • Mirror Galvanometer
  • Ballistic Galvanometer
There are seven kinds of ammeters. They are:
  • Moving Coil Ammeter
  • Electro-dynamic Ammeter
  • Moving Magnet Ammeter
  • Moving Iron Ammeter
  • Hot Wire Ammeter
  • Digital Ammeter
  • Integrating Ammeter
3. The magnitude of direction and current is measured through a galvanometer. Ammeter is used for measuring only the magnitude of a current.
4. A galvanometer works due to the magnetic field present in a current. Ammeter is capable of working with or without the magnetic field.
5. The direct current is measured through the galvanometer. The direct and alternative current is measured through an ammeter.
6. Bridges and potentiometers use this instrument for detecting the current. Ammeters are used in electric circuits.
7. A galvanometer is less accurate. The accuracy rate of an ammeter is high.
8. A galvanometer has high sensitivity. An ammeter has low sensitivity.
9. A galvanometer is capable of showing the direction in which the current flows. The magnitude of the current is measured through an ammeter.
10. A galvanometer is a mechanical device. The ammeter can either be a mechanical or an electronic device.
11. The resistance rate of a galvanometer is moderate, i.e., 10-100 ohms. The resistance rate of an ammeter is zero.

So, these are some of the contrasting points regarding the galvanometer and ammeter. Now, there are certain advantages and disadvantages associated with both of them. So, let us have a look at them.

Advantages of Galvanometer

  1. A galvanometer has high accuracy and reliability.
  2. The rotation/ force in a galvanometer is high.
  3. The sensitivity of a galvanometer is high.
  4. The scale of a galvanometer is quite uniform.
  5. A galvanometer is not affected by magnetic fields.

Disadvantages of Galvanometer

  1. Any kind of overload can spoil the galvanometer.
  2. The rotation/ force cannot be restored easily.
  3. The rotation/ force can be changed through a change in temperature.
  4. A galvanometer cannot be used to measure alternative current (AC).

Advantages of Ammeter

  1. An ammeter is portable as well as strong.
  2. It has no effect of the earth's magnetic field.
  3. The readings of an ammeter are quite accurate.
  4. The magnitude of a current is measured through an ammeter.
  5. An ammeter is used in both alternative current (AC) and direct current (DC).

Disadvantages of Ammeter

  1. Sometimes an ammeter can be quite heavy to carry.
  2. Multiple meters are used in measuring different ranges of amperage.
  3. The ammeter cannot store data.
  4. The accuracy rate of the device is reduced.
  5. The heat and magnet might affect the magnet.

So, these are some of the advantages and disadvantages of galvanometers and ammeters. Both these instruments are used for measuring electric currents. They are portable and accurate. Thus, both galvanometer and ammeter are essential instruments for measuring a small and wide range of currents.

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