3582428630

Composed by Dr U S Mirdha

MITS,Jadan

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Experiment No -__

Objęci:

To deternune the fcrromagnelic constants; retenliviiy. pcnncability and susccpiibility by tracing J-H curve using CRO

Apparatus required:

Setup hysteresis loop mcasuremeni and CRO

To Y platc

Formula used:

The spec i men is pul inside the solcnoid and is subjectcd to a varying magnet ic field H. the magnetic field H is produced by passing a.c. currcnt in the solcnoid is given by

H =

*rrr.\ 2 Irms 10

COS U) t

Where lnu is the currcnt in amperc and n is the number of turns per cm. in primary coil of solcnoid.

The potcntial differcnce devcloped across 1 ohm resistor Ri is fed to XX piąte of CRO and consequent!y. X-deflection will be proportional to H.

The emf (e) across the secondary coil is measured of dB/dt and not of magnetic flux density B. hence. an integrating Circuit (using 47kQ resistance and 2pF capacitor) is used. Thcn. the potential differcnce across 2pF condenser at any instance is

o

r

Provided R > > reactance of the circuit. This potential differcnce proportional to B. is applied to Y-deflection platc of CRO. Thus. we obtain a hysteresis (B-H) curve on CRO screen. by displaying 11 on X- and B on Y- deflection plates.

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