Which of the following is NOT a type of comparator?

Concept:

A comparator is an indirect type of instrument with the help of which an unknown dimension of a workpiece is compared with a working standard (usually slip gauges).

Comparators are classified as:

• Mechanical Comparators: In These mechanical means are used to get the magnification, for example, gear system, levers, etc. Types:
  • Dial indicators
  • Lever comparators
  • Reed type comparator
  • Sigma comparator
  • Johansson Mikrokator Comparator
• Electrical Comparator: In this, the movement of the measuring contact is converted into an electrical signal. This electrical signal is recorded by an instrument that can be calibrated in terms of plunger movement.
• Optical Comparators: This type of comparator uses fundamental optical law and instead of a pointer, the edge of a shadow is projected onto a curved graduated scale to indicate the comparison measurement.
• Pneumatic Comparator: In these comparators, either airflow or air pressure is measured to give measurement deviation from a standard. The response of the comparators working on airflow is quicker than those working on air pressure, but the latter is more versatile than the former.

• Hydraulic Comparator: The hydraulic comparator is similar to a hydraulic deadweight tester except that, instead of a piston and weight assembly, a master test gage is employed. One type of hydraulic comparator is specified for military use. This unit is designed for opera- tion on light and medium weight oils, water, gasoline, alcohol, kerosene, and glycerine gages,