Difference Between Galvanometer and Ammeter for JEE Main 2025

In this article we will learn about the differences between ammeter and galvanometer. An ammeter and galvanometer both are used to measure the flow of current in the electric circuit though they have many differences between each other.

The ammeter only displays the current’s magnitude flowing in the electric circuit whereas the galvanometer displays both direction and magnitude of the current flowing in the electric circuit. However there are many differences but this property is the main difference between the ammeter and galvanometer. We will come to know about the other differences between these two further in this article.

Explain Galvanometer and Ammeter:

Galvanometer:

In the realm of electrical measurements, a galvanometer is a device used to detect and measure small electric currents. It is a crucial instrument in various fields, including physics, electronics, and telecommunications. The galvanometer's working principle is based on the interaction between a magnetic field and an electric current, allowing for the measurement of current strength. Let's delve into the details of a galvanometer.

Working of Galvanometer 

A galvanometer consists of a coil of wire suspended between two poles of a permanent magnet. The coil is typically wound around a soft iron core to enhance its magnetic field interaction. When an electric current passes through the coil, it generates a magnetic field around it. Simultaneously, the permanent magnet exerts a magnetic field on the coil. According to Ampere's law, these two magnetic fields interact, causing a torque to be applied to the coil.

The torque tends to rotate the coil, and the extent of rotation depends on the strength of the current passing through the coil. The coil is attached to a thin pointer that moves along a calibrated scale, indicating the magnitude of the current. The deflection of the pointer is directly proportional to the current passing through the galvanometer.

Terms Related to Galvanometer

Current- Electric current can be defined as  flow of charged particles which can be electrons or ions .It’s S.I. The unit is Ampere. 

Electric Circuit- The electric circuit can be defined as a closed loop or path which forms a network of electrical components where electrons can flow.

Open Circuit- It is a circuit in which there is no flow of current, that means the path is incomplete.

Closed Circuit- It is a circuit in which there is flow of current that means the path is complete.

Ammeter:

An ammeter is an essential device used to measure the flow of electric current in a circuit. It is commonly employed in various fields, including electronics, electrical engineering, and physics. The primary purpose of an ammeter is to provide an accurate measurement of current strength, enabling engineers and scientists to analyze and troubleshoot electrical circuits effectively. Let's explore the ammeter's working principle and its significance in electrical measurements.

Working Principle:

The working principle of an ammeter is based on the concept of current shunting. When an ammeter is connected in series with a circuit, the entire current flowing through the circuit also passes through the ammeter. The ammeter is designed with a low resistance to minimize the voltage drop across it, ensuring that it does not significantly affect the circuit's current.

To achieve this, an ammeter is often constructed using a galvanometer, which is a sensitive instrument that detects and measures small electric currents. The galvanometer coil is connected in series with a resistor known as a shunt resistor. The shunt resistor has a very low resistance value compared to the circuit being measured. As a result, most of the current is diverted through the shunt resistor, while only a small fraction flows through the galvanometer coil.

Terms Related to Ammeter 

CURRENT- It can be defined as flow of charged particles which can be electrons or ions .Its SI unit is ampere.

Types of ammeters: ammeters can be of many types which are mentioned below.

Based on construction:

• Permanent moving coil ammeter ( PMCA)

• Moving iron ammeter 

• Electro – dynamo ammeter

• Rectifier type ammeter

Based on the measurement of current

• AC Ammeter

• DC Ammeter

• Analog ammeter 

• Digital ammeter

Real Life Uses of Galvanometer 

• Galvanometers have many uses ,some of which are listed below:

• They are used in modern automobiles and heavy mechanical engineering to position and regulate their systems.

• They are very useful in laser televisions, laser displays and are required for laser beam welding.

• A galvanometer is also useful in the measurement flow direction of current .

• A galvanometer is used in the laboratories of schools and colleges to study the basic principles of the instrument and to determine the current.

Characteristics of Galvanometer and Ammeter

Real Life Uses of Ammeter:- 

Ammeter is used in numerous ways, some of its uses are listed below :-

• Ammeter is a device used to measure electric current .

• It is mainly used in electrical systems such as in businesses and home to measure the flow of electricity.

• An ammeter measures both AC and DC current .

• In day to day life it can be used anywhere to measure the current like in cars ,sensitive machines ,heaters, fridge etc.

Application And Significance:-

Galvanometers and ammeters are essential tools in electrical engineering. They find applications in various areas, including circuit analysis, electronics, telecommunications, and power systems. Here are some key uses of these instruments:

Fault Detection: Galvanometers are employed in fault detection systems to monitor and identify faults in electrical networks. By detecting abnormal current levels, these devices help engineers locate and rectify faults promptly.

Circuit Design: Galvanometers and ammeters are utilized during circuit design to measure current flow, ensuring that the designed circuit operates within specified limits. This helps in selecting appropriate components and ensuring circuit efficiency.

Electrical Safety: Ammeters play a crucial role in ensuring electrical safety. By accurately measuring current, they help in assessing whether electrical devices or circuits are operating within safe limits. This information is vital in preventing overheating, electrical fires, or other hazardous situations.

Component Testing: Galvanometers are utilized to test the performance and characteristics of various electrical components. By measuring current levels during component testing, engineers can assess their functionality and verify their specifications.

Galvanometer and Ammeter Difference 

Summary :-  

Galvanometers and ammeters are indispensable tools for measuring electric currents in a wide range of applications. Their accurate and precise measurements enable engineers and technicians to analyze circuits, ensure electrical safety, and design efficient systems. Understanding the principles and applications of these instruments is essential for success in exams like JEE mains and for a career in electrical engineering.