A Vernier caliper is referred to as an instrument that is commonly used for a variety of accurate measurements and is not necessarily related just to the engineering manufacturers. There are three types of Vernier caliper that are commonly used in the laboratory in order to measure the lengths of the small objects accurately precisely which cannot be done using a meter scale or any other instrument. So, let’s scroll down to learn more about the types of Vernier caliper.

- Type A
- Type B
- Type C

The foremost use of any Vernier caliper is to measure the internal as well as the external diameter of an object. The word caliper is derived which means any instrument with two jaws that are used to determine the diameters of objects. This is the instrument that is well known for obtaining accurate measurements which are highly required for scientific experiments.

The principle on which a Vernier caliper works is that whenever there are two scales or divisions which are slightly different in size, then the difference within them is used so that the accuracy of the measurement can be increased.

**Parts of Vernier Caliper**

A Vernier caliper is high in demand at places where there is a requirement for highly accurate measurement. So here comes a need to properly know the elements of Vernier caliper which are mentioned below. So, the main elements of the Vernier caliper are as follow:

- Main Scale
- Vernier scale
- Thumbscrew
- Lock screw
- Depth Rod
- A fixed jaw, and
- Sliding jaw
- Description

**The Principle of Vernier Caliper**

A scale cannot measure objects which are smaller than 1mm whereas a Vernier caliper can measure objects up to 1mm. As is well known that the Vernier caliper is found to have two scales the main scale and the Vernier scale, both of these make an arrangement to measure very small lengths like that of 0.1mm and so on. The main scale is found to have the least count of 1mm whereas the Vernier scale has the least count of 0.9mm. 10 units of the main scale are equivalent to 1cm whereas 10 units of the Vernier scale is equivalent to 0.9mm.

The unit of the Vernier scale is millimeters. This is termed as the main difference between the main scale and the Vernier scale which is 0.1 mm and is also referred to as the working principle of the Vernier caliper.

**Least Count Of A Vernier Caliper**

The difference between the values of one main scale division and that of a Vernier scale division is referred to as the least count of the Vernier caliper. The least count of the Vernier caliper is referred to as the smallest value which can be measured from this instrument. In order to calculate the least count of a Vernier caliper, the value of one main scale division needs to be divided by the total number of divisions present on the Vernier scale.

For example, if the value of one main scale division is 1mm and the total number of divisions on the Vernier scale is found to be 10mm then the least count will be 0.1mm. Therefore, the least count is known to be the smallest distance which can be measured from an instrument named Vernier caliper.

**Zero Error in Vernier Caliper**

Zero error in the vernier caliper is referred to as a mathematical error due to which, the zero of the vernier scale does not get coincided with the zero of the main scale. In case the zero mark on the vernier scale does not coincide with the zero mark on the main scale, then the error which is found to occur is termed as zero error. Zero errors are found to be of 2 types which are as follows:

- Positive zero error
- Negative zero error

**1. Positive Zero Error**

In the case of positive zero error, if these jaws are brought together the observer can see the zero of the Vernier scale will be ahead of the main scale zero. It can be said that the zero of the Vernier scale is at the right side of the main scale zero. In both cases either it is ahead of the main scale zero or it would be at the right side of the main scale zero. This is referred to as the zero error which is positive.

**2. Negative Zero Error**

In case of negative zero error, once both the jaws are brought together the observer can see zero of the Vernier scale which is at the backside of the main scale zero, or can also be at the left side of the main scale zero. So in case, the Vernier scale zero is found to be at the backside or to the left of the main scale zero then in both the cases, zero error is found to be the negative error.

**3. No Zero Error**

In no zero error, once both the jaws are brought together the observer can see zero of the Main scale coinciding with the zero of the Vernier scale. If they are exactly in a straight line then the Vernier caliper is said to be free from zero error or can be said that there is no zero error in this Vernier caliper.

**Types of Vernier Caliper**

- Flat edge Vernier caliper
- Knife-edge Vernier caliper
- Vernier gear tooth caliper
- Vernier depth gauge
- Flat and knife-edge Vernier caliper
- Vernier height gauge
- Vernier dial caliper

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