Resistance and Figure of Merit of a Galvanometer

A galvanometer is a device used to detect weak electrical waves in a circuit. It consists of a coil hanging between the poles of a powerful magnet. As the current passes through the coil, it deviates. It can be detected by deviation from the galvanometer needle. The deviation is in line with the current flow.

 The Galvanometer is an electromagnetic device used to find very low value of current. Its performance is based on the principle set by the coilin the same magnetic field feels torque when electricity is installed in it. The deviation of the coil determines the attached pointer in it, that moves on the scale. When the coil holding the current I is placed in a bright magnetic field, the coil undergoes deviation θ related to me as

    I = k θ

where k is the constant consistency and is called the figure of galvanometer accuracy.

THEORY

MOVING COIL GALVANOMETER-

A moving  coil galvanometer is a tool used to measure electrical waves. It is a sensitive magnetic device that can measure low frequencies even the shape of a few microamperes.

Moving galvanometers are mainly divided into two types:

   1.The fixed coil galvanometer

   2.Pivoted-coil or Weston galvanometer

Coil Galvanometer Distribution System

The coil holding current when placed in the external magnetic field feels magnetic torque. The angle at which the coil is diverted due to the effect of magnetic torque is equal to the current size of the coil.

A moving coil galvanometer is made of rectangular coil and is usually made of thin or thin closed wire wound on a metal frame. The coil is free to rotate about a fixed axis. A phosphor-bronze fiber attached to a moving head is used to position the coil in the same magnetic field.

The most important properties of materials used for coil suspension are conductivity and low torsional constant value. The cylindrical soft iron core is evenly placed inside the coil to improve the magnetic field performance and to make the field more radiant. The lower part of the coil is attached to a phosphor-bronze spring with a small number of turns. The other end of the spring is connected to the binding screws.

Galvanometer

A galvanometer is a device used to detect small amounts of electrical energy or to measure its magnitude. The current and its intensity are usually indicated by the movement of the magnetic needle or that of the coil in the magnetic field which is an integral part of the galvanometer.

A galvanometer is a tool that can detect and measure small amounts of current in an electrical circuit. The first galvanometer was built a few months after Hans Christian Ørsted showed in 1820 that electrical power could divert a magnetic needle. The machine was assembled by mathematician and German physicist Johann, who called it a duplicate. In fact, a galvanometer consists of such a needle attached to a coil inserted that the coil is allowed to move freely in a magnetic field made of one or more magnetic poles. When electricity is allowed to pass through the coil, the magnetic field produced by the current cable connects to the field of permanent grains (moving from north to south poles), producing a twisting force known as torque around the coil, a response defined by the left-handed law. The deviation of the galvanometer needle is equal to the still flow of the coil.

A simple, needless galvanometer was introduced in this study. To see the electrical power on the coil, click the blue Open button to turn the Knife Switch on. This action allows the energy from the battery to flow through the circuit (from positive to negative), with a coil placed between the opposing poles of the two Magnets. The magnetic field generated by the current in the coil is at right angles to the coil plane; the field is marked by purple arrows, the tips of which point to the northern end of the field.

 This magnetic field causes the coil to vibrate, as the pole on the south side of the coil’s magnetic field is attracted to the north pole of the bar’s magnetic field. Once the coil is aligned in this way it does not move again unless the cable goes straight to the coil by pressing the Flip Battery button. This action reverses the magnetic field poles generated near the coil as the current passes through it, so the coil turns in the opposite direction. To stop the power supply on the coil, click the red Close button.

Tangent galvanometer

The Tangent galvanometer is an early measurement tool for small electrical waves. It consists of a copper wire wound  enclosed in a non-magnetic circular frame. Its effectiveness is based on the principle of the tangent law of magnetism. When a current is passed through a circular coil, a magnetic field (B) is produced in the center of the coil in a manner similar to the coil plane. The TG is arranged in such a way that the horizontal part of the earth’s magnetic field (Bh) is directed toward the coil plane. The magnetic needle is then under the action of two fields mutually perpendicular. If θ is a needle deviation, then according to the tangent rule,

 B = Bh (tanθ) 

CONCLUSION

lock key K2 and adjust the resistance value in the resistance box RBOX 2, you get a deviation θ / 2 on the galvanometer. S I as I = kθ, where uk is a constant equation and is called the galvanometer accuracy model.

An example of a galvanometer suitability is that a large amount of current is transmitted through a galvanometer to produce a one-part deviation from the scale.