A vernier caliper is a precise measuring instrument used for determining linear dimensions and diameters of round objects. Let’s explore its key features:

1. Definition and Purpose:

   • A vernier caliper is a measuring device that provides accurate and precise measurements.
   • It is commonly used to measure lengths, widths, and diameters.
   • The device consists of two graduated scales: the main scale and the vernier scale.

2. Parts of a Vernier Caliper:

   • Main Scale: The larger scale with evenly spaced divisions.
   • Vernier Scale: A smaller scale that slides along the main scale.
   • Jaws: Used to measure external and internal dimensions.
   • Depth Rod: Measures the depth of holes or recesses.

3. Least Count:

   • The least count (or vernier constant) is the difference between one main scale division and one vernier scale division.
   • Mathematically: LC = 1 MSD – 1 VSD
   • For most vernier calipers, the least count is 0.1 mm.

4. Zero Error:

   • Zero error occurs when the caliper registers a reading when it should read zero.
   • Two types:
     • Positive Zero Error: Reading is positive and away from the actual zero (e.g., +0.08 mm).
     • Negative Zero Error: Reading is negative and away from the actual zero (e.g., -0.10 mm).

5. How to Read a Vernier Caliper:

   • Align the scales.
   • Read the main scale value.
   • Identify the vernier scale division that aligns with a main scale division.
   • Add the vernier scale reading (VSR) multiplied by the least count (LC) to the main scale reading (MSR).