Angular velocity is measured using devices called tachometers.
Tachometers are instruments that measure angular speed by registering anyone of the following
Number of rotations during the contact period (or)
- Number of rotations per minute (rpm)
- Tachometers are classified as follows:
Mechanical Tachometers
- Revolution counter and timer
- Tachoscope
- Hand speed indicator
- Slipping clutch tachometer
- Centrifugal force tachometer
- Vibration reed tachometer
Electrical Tachometers
- Drag cup tachometer
- Commutated capacitor tachometer
- Tachogenerators
- DC – Tachogeneraor
- AC – Tachogeneraor
Contact Less Electrical Tachometers
- Inductive pick up tachometer
- Stroboscope tachometer
- Photoelectric tachometer
- Capacitor tachometer