calculation of least count in metric & imperial

8/20/2019 Calculation of Least Count in Metric & Imperial

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CALCULATION OF LEAST

COUNT IN METRIC &

IMPERIAL SCALESBy: VerniersCaliper.com


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WHAT IS A LEAST COUNT?

A scale is the defining feature of any measuring

instrument. Usually measurements are taken by

placing an object on top of a scale and noting the

distance between the edges. In this case a larger

number of divisions on the scale leads to a moreaccurate measurement and vice versa.


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The technical term used to describe this parameter is

known as least count, which is the smallestmeasurement which can be measured by a scale. Its

value can be obtained by the division of one unit on the

scale by the number of divisions that lie in between.


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REMEMBER

The correct determination of the least count of a

vernier caliper is important for the measurement

to be accurate. This is a common difficulty faced

by people, even engineers and leads to incorrect

readings while measuring heights, diameter,lengths etc. Sometimes both metric and imperial

units together on the scale may also cause

confusion.


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ABOUT

This article will tell you the procedure for

calculating the least count of a vernier caliper.

The smallest measurement which can be

recorded by the Vernier caliper is defined as the

least count.


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DETERMINE THE

LEAST COUNT

First we need to determine the least count of the main

scale which can be done as described previously. Then

we need to count the number of divisions on the vernier

scale and divide the least count of the main scale by it.

This will give us the least count of the vernier caliper.

The formula for this can be expressed as:

Least Count of Vernier Caliper = Main Scale

least count/ number of Vernier scale divisions


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CALCULATION OF LEAST

COUNT OF VERNIER

CALIPERS IN METRIC SCALE

In metric scales, the units used for calibration are

millimeters i.e. one division equals 1 cm and is divided

into further divisions in millimeters. The least count

can be calculated by dividing 1 cm by the number ofdivisions that lie between a unit. This way a main

scale which contains 10 divisions in a centimeter will

have a least count of 1/10 = 0.1cm or 1 mm.


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Similarly the vernier scale is also normally divided into

ten equal parts. Count the divisions on the vernier

scale just to make sure. The least count of the vernier

caliper can now be found by dividing the least count ofthe main scale by the number of divisions on the

vernier scale.

Usually the least count of the main scale is 0.1 m andthe vernier scale has 10 divisions so the least count

would be0.1/10 = 0.01cm.

The least count is related to accuracy in such a way thatif a vernier caliper has a least count of 0.01cm then it

is said to also have an accuracy of 0.01 cm.


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if you want to calculate the least count in mm, here isthe formula below:

Vernier caliper least count in mm = Vernier caliper least

count incm x 10

So in this case it would be;0.001 x 10 = 0.01mm,

therefore0.01 mm is the least count in millimeters for

this Vernier caliper.


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CALCULATION OF

LEAST COUNT OF VERNIER CALIPERS IN

IMPERIAL SCALE

There are two types of imperial Vernier calipers

discussed in the examples:


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TYPE 2 IMPERIAL VERNIER

CALIPERS

If there are 25 divisions on the Vernier Scale

If the vernier scale is divided into 25 parts then the

smallest measurement possible from the main scale

would be 0.025 inches.

Therefore least count of the Vernier Caliper is

calculated by the same formula i.e. dividing 0.025

by 25 = 0.001 inch

We can say that 0.001 inch is the accuracy and least

count for type 2 of imperial Vernier Caliper.


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For Further Information

Related to the Topic of

Calculation of Least CountIn Vernier Caliper
http://vernierscaliper.com/vernier-caliper-calculation-of-least-count-in-metric-imperial-scales-213.htmlhttp://vernierscaliper.com/vernier-caliper-calculation-of-least-count-in-metric-imperial-scales-213.html

calculation of least count in metric & imperial

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