How are galvanometers constructed?
Modern galvanometers, of the D’Arsonval/Weston type, are constructed with a small pivoting coil of wire, called a spindle, in the field of a permanent magnet. The coil is attached to a thin pointer that traverses a calibrated scale. A tiny torsion spring pulls the coil and pointer to the zero position.
What is working principle of a moving coil galvanometer?
A moving coil galvanometer works on the principle that a current-carrying coil placed in a magnetic field, experiences a torque. The coil springs along with the radial field ensure the deflection to be proportional to the strength of the current.
Which material is used for making galvanometer?
Soft iron
Soft iron is used in making the core of moving coil galvanometer, because it has high initial permeability and low hysteresis loss.
What are the types of moving coil galvanometer?
There are mainly two types of moving coil galvanometers:
- Pivoted coil galvanometers: It consists of a rectangular coil rotating freely on a vertical axis between a horseshoe magnet.
- Suspended coil galvanometers: It consists of a rectangular coil suspended between the two poles of a magnet from a movable torsion head.
How are ammeters constructed?
An ammeter is constructed by connecting a shunt resistance Rsh in parallel to the movement, and the whole set up, that is, the movement and the shunt resistance constitute the constructed ammeter (see figure below).
What are the internal components in a galvanometer?
The main parts in this instrument mainly include the suspension, moving coil, & stable magnet. This is the current-carrying element in the galvanometer. This coil is in a circular otherwise rectangular shape with the no. of twists of copper wire.
Why concave mirror is used in moving coil galvanometer?
The pole pieces of the galvanometer are made concave so that the current-carrying coil and the magnetic field are always perpendicular to each other. Concave magnetic pole always produces a radial magnetic field. The radial field will always be perpendicular to the conductor rotating about the axis.
What is sensitivity of galvanometer?
The current sensitivity of a galvanometer is the deflection per unit current produced by the galvanometer. A high-sensitivity galvanometer can be used to measure very low values of currents. A low-sensitivity galvanometer can be used to measure high values of currents.
What is galvanometer give its construction and working?
Definition: An electromechanical instrument that is used for noticing & signifying an electric current is known as galvanometer This works as an actuator by generating a rotational deflection in reply to the flow of current throughout a coil in a stable magnetic field.
Why iron core is used in galvanometer?
A soft iron core is used in galvanometer because the magnetic lines of force can be attracted by the soft iron core. This attraction of magnetic lines of force increases the magnetic field which increases the sensitivity of galvanometer.
What are the parts of galvanometer?
What is the resistance of galvanometer?
The resistance of a galvanometer is 50 ohm and the maximum current which can be passed through it is 0.002 A.
How can ammeters and voltmeters be constructed from galvanometer?
An ammeter is an instrument used to measure the current passing through a circuit. A galvanometer can be converted into ammeter by connecting a low resistance called shunt in parallel to the galvanometer. A voltmeter is a device used to measure the potential difference between two points in a circuit.
What are the two basic components of a galvanometer?
Answer: The moving coil , suspension and permanent magnet are the basic elements of galvanometer.
Why horseshoe magnet is used in galvanometer?
Solution. In moving coil galvanometer, strong horse shoe magnet of concave shaped pole pieces is used to produce magnetic field which is parallel to plane of coil at any position.
Which magnet is used in galvanometer?
The shape of magnet in moving coil galvanometer to make the radial magnetic field is concave magnets.
What is SI unit of galvanometer?
The SI unit of current sensitivity of galvanometer is division/ampere (or) radian/ampere.
What is unit of sensitivity?
Unit of instrument sensitivity is expressed in Ohm/Volt. Sensitivity is also expressed as: S e n s i t i v i t y = 1 a m p e r e. So, sensitivity is said to be equal to the reciprocal of the full-scale deflection current.
Why phosphor bronze wire is used in galvanometer?
In galvanometer, phosphor bronze wire is used because this wire has a small restoring torque per unit twist and the tensile strength of this wire is high.
What is sensitivity of a galvanometer?
What is the unit of galvanometer?
What is the SI unit of galvanometer?
What is K in galvanometer?
Here k is called the torsional constant of the spring (restoring couple per unit twist). The deflection or twist θ is measured as the value indicated on a scale by a pointer which is connected to the suspension wire. θ= ( nAB / k)I. Therefore θ ∝ I. The quantity nAB / k is a constant for a given galvanometer.