Hey !!
What is Tangent Galvanometer ? Construction and principle + working.
Proper explanation needed.
CBSE BOARD EXAMINATION
Answers
Hi,
Here is your answer,
Construction
Tangent Galvanometer consists of a non-magnetic circular vertical frame on which three separate circular coils of insulated wire having 2, 50 and 500 turns are wounded. The ends of these coils are connected to the screws provided over the base of the instruments,
The vertical frame (or coil ) can be rotated about a vertical axis passing through the centre of the instruments. A circular compass box made of non-magnetic material is fitted at the centre of the vertical frame. Three levelling screws are provided to the base to make the base as horizontal.
PRINCIPAL AND WORKING
The instruments is levelled with the help of levelling screws. The plane of the coil is gently rotated so that it is parallel to magnetic induction meridian.Now the compass box is rotated till the aluminium pointer reads 0° - 0°.
When, no current flows through the coil, the magnetic needle will be along the magnetic meridian. When a current i is passed through he coil, magnetic Induction field B is set up at the centre of the coil. The horizontal component is earth's magnetic field BH will be at right angles to B since BH is in the plane of the coil. The magnetic needle is under the action of B and BH which are mutually perpendicular.
Now, from TANGENT LAW B = BH tanθ
B = μ/2.ni/r
Here, number of turns of the coil, i is the current through the coil, and r is the radius of the coil,
So, μ/2.ni/r = BH tanθ (or) i = (2rBH/μοn) tanθ
(OR) i = Ktanθ
where, K = (2rBH/μοn) is a constant called reduction factor of the tangent galvanometer.
So, therefore current 'I' is to measured is directly proportional to the tangen t of the angle of deflection. Since, galvanometer works based on tangent law it is called tangent galvanometer.
HOPE IT HELPS YOU !
