Tachometer Purpose, Types and Application


Tachometer is a sensor and measuring device that can measure the revolution speed of the rotating objects. It is used for measuring the rotation speed of objects such as a shaft or disk, in the motor of the motor vehicles or in other machines where rotation speed is the driving force. The measurement unit is ‘revolutions per minute’ (RPM) of the rotating object.



Tachometer is comprised of a dial, needle and markings. The needle of the device indicates the result received, while the markings (high and low) indicate safe and dangerous levels of the rotating speed that is measured.


The usage of this device is of crucial importance for measuring the rotating speed of the shaft or the motor in every vehicle. Given this, this device enables the driver of the motor vehicle to track the rotating speed and with that to adjust throttle and the gear to the driving conditions. This is important because if the vehicle keeps running under prolonged speed, it can lead to insufficient lubrication. The insufficient lubrication can affect the work of the engine or in worst cases, it can cause a breakdown. For this reason tachometer is indispensable part of any vehicle gear.


There are several types of tachometers, classified on basis of the working principle, usage and construction. Some of the main types of tachometers are:

  • DC Tachometers;
  • AC Tachometers;
  • Mechanical Tachometers;
  • Analog Tachometers;
  • Digital Tachometers.


As we’ve mentioned before, tachometer is used for measuring the rotating speed of the rotating objects and for that reason this device is used in motor vehicles. But, the use of this measuring device is much broader. Namely, the tachometer is used in:

  • Marine fleet, for measuring the rotating speed of the marine diesel machines on the board ships. This device shows the direction towards which the ship rotates.
  • Broad range of vehicles such as: automobiles, tractors, tucks, airplanes, trains and other light rail vehicles.
  • Medicine, the device known as haema-tachometer, is used for estimating the blood flow rate.
  • Many laser instruments and devices.

Reference: Principle, Types and Application of Tachometer