What Is a Comparator?
A comparator is an exact tool that is used to compare the dimensions of a given workpiece component with the actual work standard. Different types of comparison are available.
Types of Comparators
Based on the method of magnification, the comparators are classified as follows:
- Mechanical Comparator
- Mechanical-Optical Comparator
- Reed Type Comparator
- Electrical-Electronic Comparator
- Pneumatic Comparator
#1. Mechanical Comparator
- A mechanical comparator employs mechanical means to obtain magnification, for example, levers, gear systems, etc.
- Its construction requires a high degree of skill and precision.
- The magnification of a mechanical comparator varies from 250 to 1000.
#2. Mechanical-Optical Comparator
- In mechanical, optical comparators, small displacements of the measuring plunger are first amplified by a mechanical system consisting of perforated levers.
- The amplified mechanical movement is further enhanced by a simple optical system involving the projection of an image.
- The general arrangement employed is such that the mechanical system causes an aircraft reflector to tilt about an axis, and the image of an index is projected onto a scale on an internal ground-glass screen.
- Optical magnification provides a high level of measuring accuracy for lack of movable members and better wear resistance properties.
#3. Reed Type Comparator
- The device used to measure the linear displacement of the spindle with the help of a reed mechanism is known as a reed type mechanical comparator.
- It is a device for increasing the low speed of the spindle.
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Constructional details :
- The reed mechanism is a frictionless device for increasing the low speed of the spindle.
- It consists of a fixed block ‘A,’ which is rigidly fastened to the gauge head case.
- The floating block ‘B’ carries the gauging axis.
- The floating block is also horizontally attached to the block defined by `C`
- A vertical reed is attached to each block in which the upper ends are joined together.
- These vertical reads are shown with the letter ‘D’ in fig.
- A pointer is attached to this joint.
#4. Electrical-Electronic Comparator
- These comparators depend on the Wheatstone bridge circuit for their operation. In d.c.
- There is a change in the balance of electrical resistance in each arm of the circuit, the bridge—displacement of an armature relative to the arm under the action of the measuring rider.
- Once the balance is deteriorated by the bridge, it is measured by a galvanometer. The rider is read in units of linear movement. This circuit is powered by a battery.
- To bridge For equilibrium, the ratio of resistors in the two arms must be equal.
- If alternating current is applied to the bridge, the inductance and capacitance Weapons must also be accounted for along with resistance.
- In actual measuring instruments, one induction head is made by a pair of coils in the measuring head of the instrument.
- The armature creates differences in this type Induction of a pair of coil forming AC of one hand Bridge.
- The arm holds Armature and Indic- Is dependent on tance in the Relative coil displacement of armature For the coil. Other refinements are As an electrical device AL method of zero adjustments and A.
- Switch to change the magnification.
- The amount of imbalance due to measles movement- Ing rider is shown and shown on a linear scale.
- Order magnification of x 30,000 Is possible with this system. Commonly used equipment are elected electricity.
#5. Pneumatic Comparator
- A comparator is a device used to measure the amplitude of a given component by comparing it with the actual working standard.
- Pneumatic means air is used for the magnification of measured measurements, as compared to air and pneumatic.
- Pneumatic comparators operate on the principle that if an air jet is in close proximity with a surface, the flow of air from the jet is restricted, which changes the air pressure in the jet-supplying system.