Question

why the pointer of measure is in any place on the scale will it is in idle​

Answer 1

Answer:

Analogue displays have a pointer which moves over a graduated scale. They can be difficult to read because of the need to work out the value of the smallest scale division. For example the scale in the picture has 10 small divisions between 0 and 1 so each small division represents 0.1. The reading is therefore 1.25V (the pointer is estimated to be halfway between 1.2 and 1.3).

The maximum reading of an analogue meter is called full-scale deflection or FSD (it is 5V in the example shown).

Analogue meters must be connected the correct way round to prevent them being damaged when the pointer tries to move in the wrong direction. They are useful for monitoring continously changing values (such as the voltage across a capacitor discharging) and they can be good for quick rough readings because the movement of the pointer can be seen without looking away from the circuit under test.

Explanation:

Taking accurate readings

To take an accurate reading from an analogue scale you must have your eye in line with the pointer. Avoid looking at an angle from the left or right because you will see a reading which is a little too high or too low. Many analogue meters have a small strip of mirror along the scale to help you. When your eye is in the correct position the reflection of the pointer is hidden behind the pointer itself. If you can see the reflection you are looking at an angle.

Instead of a mirror, some meters have a twisted pointer to aid accurate readings. The end of the pointer is turned through 90° so it appears very thin when viewed correctly. The meter shown in the galvanometers section has a twisted pointer although it is too small to see in the picture.