Indicating Instruments

Construction of Indicating Instruments

The Construction of indicating instruments have the following main parts.

Moving System

The basic part of indicating instrument is the moving system. Moreover, This moving system is place in the middle of deflects according the field of quantity provide to it. the pointer is place at the moving system of the indicating instrument. the deflection of moving system gives birth to the pointer and the pointer moves on the scale which gives us the reading of the required quantity.

Permanent Magnet

Permanent magnet is use for the main flux of indicating instruments.These are normally made of steel. In which the cobalt and chromium are dope in the construction of the permanent magnet. Moreover, Alnico is also use in the construction of permanent magnet.

the magnetism of these permanent magnets should not be decrease with the passage of time. In few instruments electromagnetic coils are use instead of permanent magnet.


The pointer use for the reading of electrical quantity pointer is use. these pointers are connect with the moving system.and indicates the position of the moving system.

The pointer size and shape depends on the instrument. Pointers should be use with least weight that no extra damping force is require for the movement of pointer.


The scales are use for the reading of electrical quantity measurement. The scales are equally graded lines which place at the meter screen known as Scale.The reading is past over the aluminium or plastic with black dotes or lines. Mostly, the zero scale is pace at the left side and the maximum range at the right side of the scale. while the ohmmeter scale is usually the opposite sometime the zero scale is in the middle of the scale.

Controlling Spring

In few indicating instruments for the purpose of torque spring is use.the one side of the spring is connect with the spindle and the other is connect with the static part of the instrument. mostly, the spring are hair spiral or strip spiral types use in these instruments.

These springs are made of phosphor bronze material. they are also made of silicon, bronze, platinum ,iridium, and German silver.


The outer body of an instrument is call casing. These are made of cost iron, steel etc.


Indicating instruments are commonly use in home, collages, laboratories, workshop etc.

Construction of Indicating Instruments

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