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# Vernier caliper

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This experimental presentation explains about the usage of the vernier caliper.
It starts with a definition of the vernier caliper, then goes on introducing the parts, errors, special definitions and as to how a measurement could be taken.

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### Vernier caliper

2. 2. See the video format of this Presentation at: https://www.youtube.com/watch?v=uVBJkJrYN1I See more of my videos at : https://www.youtube.com/channel/UCVFSs7LUN4DSr0a4kkGt4Ag
3. 3. Like the micrometer screw gauge, the vernier caliper is used to take measurements that are accurate to within .001 of an inch or .02 of a millimeter or in other words it’s used to make very precise measurements which cannot be accurately measured from a meter scale INTRODUCTION
4. 4. PARTS OF A VERNIER CALIPER Fixed jaw Movable jaw Outer jaws Fixed jaw Movable jaw Inner jaws For internal measurements For external measurements Vernier scale Main or meter scale Fine adjustment screw Lock Depth rod (to measure depth)
5. 5. Least count- Least Count refers to the smallest distance that can be measured using an instrument. Most of the vernier Calipers have a least count of 0.1mm. Least Count = Length of 1 MSD – Length of 1 VSD Where MSD and VSD refer to Main Scale Division and Vernier Scale Division respectively Generally N divisions on main scale coincide with N-1 divisions on vernier scale 1 VSD is equivalent to (N-1)/N main scale divisions Using the formula for Least Count, we get LC = 1 MSD – 1VSD = 1 MSD – (N-1)/N MSD = 1/N MSD SPECIAL DEFINITIONS ON CALIPER MEASUREMENTS
6. 6. E.g.: A vernier scale has the length of 9 main scale divisions and is divided into 10 divisions. Since 9 divisions of the vernier scale coincide with 10 divisions of the main scale VSD = 9 / 10 mm = 0.9 mm MSD= 1 mm (the least length that can be measured from the main scale – 1/10 cm) Least Count= 1 MSD- 1VSD = 1mm - 0.9mm = 0.1mm *The least count may vary between different vernier calipers.
7. 7. Although the least count may vary between different calipers, the length formula for any caliper is as follows: Length = MSR + (VSR * LC) Where MSR, VSR and LC refer to Main Scale Reading, Vernier Scale Reading and Least Count respectively. LENGTH FORMULA FOR A VERNIER CALIPER 0 0
8. 8. Any vertical caliper may have two types of errors: 1.Positive zero error 2. Negative zero error Positive zero error – Occurs when the zero of the vernier scale is to the right of the vernier scale when the two jaws are in contact. To take the precise value for the measurement we are taking, we have to substract the value of the positive zero error from the obtained measurement. ERROR IN A VERNIER CALIPER
9. 9. Negative zero error – Occurs when the zero of the vernier scale is to the left of the vernier scale when the two jaws are in contact. To take the precise value for the measurement we are taking, we have to add the value of the negative zero error to the obtained measurement. 0 0 0 0 Positive Zero Error Negative Zero Error
10. 10. No zero error is the precise arrangement of the meter scale and the vernier scale so that the zeros of both scales fit each other as follows: To take precise measurements, we have to ensure that the caliper we are using is of no zero error. NO ZERO ERROR 0 0
11. 11. 1. First find whether there’s an error on the caliper. 2. Second find its least count(LC) 3. Place the object between the appropriate jaws (outer/inner) or on the depth rod according to the measurement. 4. The reading of the main scale (MSR) which is to the left of the zero of the vernier scale is the Main Scale Reading 5. Now look up for the no. of divisions on the vernier scale which exactly coincides with any of the main scale reading. This is the Vernier Scale Reading(VSR) 6. The length of the object is calculated using the formula: Length = MSR + (VSR * LC) 7. If there’s an error in the caliper add or substract depending on the type (positive error/negative error) TAKING A MEASUREMENT
12. 12. There are three types of measurements that can be measured with a vernier caliper. They are: 1. Measuring the external width/external diameter of an object with outer jaws 2. Measuring the internal width/internal diameter of an object with inner jaws 3. Measuring the depth of an object with the depth rod E.g.: Measuring the length of a test tube. TYPES OF MEASUREMENTS
13. 13. 1. First find whether there’s an error on the caliper. 2. Second find its least count(LC) 3. Place the object between the outer jaws 4. The reading of the main scale (MSR) which is to the left of the zero of the vernier scale is the Main Scale Reading 5. Now look up for the no. of divisions on the vernier scale which exactly coincides with any of the main scale reading. This is the Vernier Scale Reading(VSR) 6. The length of the object is calculated using the formula: Length = MSR + (VSR * LC) 7. If there’s an error in the caliper add or substract depending on the type (positive error/negative error) MEASURING WITH OUTER JAWS
14. 14. 1. First find whether there’s an error on the caliper. 2. Second find its least count(LC) 3. Place the object betweenthe inner jaws 4. The reading of the main scale (MSR) which is to the left of the zero of the vernier scale is the Main Scale Reading 5. Now look up for the no. of divisions on the vernier scale which exactly coincides with any of the main scale reading. This is the Vernier Scale Reading(VSR) 6. The length of the object is calculated using the formula: Length = MSR + (VSR * LC) 7. If there’s an error in the caliper add or substract depending on the type (positive error/negative error) MEASURING WITH INNER JAWS
15. 15. 1. First find whether there’s an error on the caliper. 2. Second find its least count(LC). 3. Keep the object in contact with the brim of the vernier caliper. Extend the depth rod until it meets the depth to be measured. 4. The reading of the main scale (MSR) which is to the left of the zero of the vernier scale is the Main Scale Reading. 5. Now look up for the no. of divisions on the vernier scale which exactly coincides with any of the main scale reading. This is the Vernier Scale Reading(VSR). 6. The length of the object is calculated using the formula: Length = MSR + (VSR * LC). 7. If there’s an error in the caliper add or substract depending on the type (positive error/negative error). MEASURING WITH DEPTH ROD Vernier caliper Object whose depth is to be measured Depth rod