Question

Search on the Internet to learn more about the instrument known as a galvanometer. Who discovered this instrument? Find out if it is available in the school laboratory and understand its parts and working. Learn about the different types of galvanometers.

Answer 1

Galvanometer

A galvanometer is a sensitive electrical instrument used to detect and measure small electric currents. It works on the principle that a current-carrying coil placed in a magnetic field experiences a turning effect, causing the coil and pointer to deflect.

The first galvanometer was developed by Johann Schweigger in 1820. He used a coil of wire around a compass needle to increase the effect of electric current. His instrument was initially called a multiplier.

A moving-coil galvanometer generally consists of a rectangular coil of insulated wire, a permanent magnet, a soft iron core, a pointer, a scale, springs and connecting terminals. When current passes through the coil, a magnetic torque acts on it and causes the pointer to move. The deflection of the pointer indicates the current flowing through the coil.

A galvanometer is commonly used in school physics laboratories for experiments involving small electric currents. Its actual availability can be checked in the school's physics laboratory.

Different Types of Galvanometers

The important types of galvanometers include:

1. Moving-Coil Galvanometer: It uses a current-carrying coil in a magnetic field and is used to detect and measure small currents.

2. Tangent Galvanometer: It uses a circular coil and a magnetic compass to measure current using the tangent law.

3. Astatic Galvanometer: It is designed to reduce the effect of the Earth's magnetic field.

4. Ballistic Galvanometer: It is used to measure the total electric charge passing through the instrument during a short current pulse.

5. Mirror Galvanometer: It uses a small mirror and a beam of light to magnify the deflection, making it suitable for detecting very small currents.