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In PMMC meter or (D'Arsonval) meter or galvanometer all are the same instrument, a
coil of fine wire is suspended in a magnetic field produced by permanent magnet. According to
the fundamental law of electromagnetic force, the coil will rotate in the magnetic field when it
carries an electric current by electromagnetic (EM) torque effect. A pointer which attached the
movable coil will deflect according to the amount of current to be measured which applied to the
coil. The (EM) torque is counterbalance by the mechanical torque of control springs attached to
the movable coil also. When the torques are balanced the moving coil will stopped and its angular
deflection represent the amount of electrical current to be measured against a fixed reference,
called a scale. If the permanent magnet field is uniform and the spring linear, then the pointer
deflection is also linear
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What is pmmc type of instruments?
Produce of series type Ohmmeter using PMMC of Ifsd:100uA for range of 0-20kohm?
Why pmmc used for DC only?
Because in the coil DC current follow easly and pmmc meter is making with coil and AC current is not follow in coil so we used the pmmc only fpr DC current.
Why pmmc instrument is cannot be used to measure ac?
Pmmc meter are most accurate instrument for DC measurement however they are unable to measure the AC quantity. The working principle is as follows: a moving coil is free to move in a external static magnetic field. And the pointer moves according to the interaction of two fields, field of static mag. and that of measuring quantity. Now in case of it is impossible to produce a sustained magnetic field, that's why we can not use PMMC to measure the ac.
Is Series resistance and PMMC used as voltmeter?
yes
Operation of PMMC instrument?
aku pon tatau
What is the explanation for the mechanism of DC in pmmc?
a pmmc has a coil suspended in permanent magnetic field.acording to the laws of electromagnetism a current carrying coil susspended in a magnetic field experiences an electromagnetic torque.This torque is counterbalanced by the mechanical torque devoloped in the coil in equlibrium.The angle teta can be measured and it is calibrated to directly give the current
What is pmmc?
pmmc stands for permanent magnet moving coil instruments these instruments are secondary measuring instruments in these instruments a permanent magnet is installed and a moving coil in this way when current is passed through the fixed coil then a force will be developed on the moving coil and thus it moves and with this moving pointer moves on the scale and gives the corresponding reading . if someone wants to read it thoroughly then he can try ashfaq hussain , j.b.gupta of basic elelctrical engg. for b.tech first year .
Why pmmc instrument measure only ac not dc?
Permanent magnet moving coil instruments are used for measuring d.c. quantities only. This is so because for these instruments the torque is proportional to the operating quantity either voltage or current.
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plastics are of 5 types[1]- polythene[2]- polyvinyl chloride (PVC)[3]- orion/polyvinyl cyanide /polyacryl nitrile (PAN)[4]- polymethyl meth acrylate (PMMC)[5]- polysterene
Definition of PMMC instrument?
An ammeter or other electrical instrument in which a small coil of wire, supported on jeweled bearings between the poles of a permanent magnet, rotates when current is carried to it through spiral springs which also exert a restoring torque on the coil; the position of the coil is indicated by an attached pointer.
Am working or I am working?
I am working
What is mean by hot working and cold working?
When ur hot and ur working then it is hot working, if ur cold and ur working then it is cold working
