There are a variety of calipers available these days namely digital, vernier and dial calipers. In this article we will be discussing the differences between a digital vernier caliper and dial caliper.
At the heart of the dial caliper lies a mechanical system made up of a rack and pinion. The dial is rotated by an internal gears system which is designed to move the dial in 0.01 mm or 0.001 inch steps. To obtain a reading, the most significant value is read from the main scale in mm or inch and the part after the decimal is read from the dial. The advantage of dial calipers is their independence from batteries and their ability to work in damp conditions.
However like everything there are some cons to them as well. The internal rack and pinion mechanism is quite delicate and can get misaligned if dropped which upsets the calibration. This is a problem because the recalibration process can be rather difficult. Also they are not as easy to read as digital calipers and come in only a single unit system either metric or imperial.
Digital Vernier Caliper
The lack of a mechanical racks, pinions or gears inside a digital caliper makes them a lot sturdier than dial calipers which is especially good for clumsy people.
Another useful feature present in digital calipers is their ability to provide measurements in both the imperial and metric systems which eliminates the need for manual conversion of units and saves a lot of hassle.
So what makes the digital caliper tick without the use of gears? The answer lies hidden beneath the plastic ruler and sliding display. Beneath the ruler is an engraved copper strip with a specific design. The sliding display on the other hand contains a comb shaped circuit board. The copper and circuit board individually behave as conductive plates while the plastic ruler behaves as a di electric.
Together this whole setup acts as a capacitor grid. The readings are taken by detecting the change in capacitance as the comb is moved along the copper strip which is due to the specific design which allows us to detect minute changes in capacitance to give precise readings.