Tachometer and encoder monitor which motor parameter?

• A. Speed
• B. Torque
• C. Temperature
• D. Position

Answer: (A)

Both devices are used to monitor motion in a motor system, focusing on rotational speed. A tachometer provides a signal that is directly proportional to how fast the shaft is turning, giving immediate speed feedback. An encoder produces pulses as the shaft rotates; by counting those pulses over time, you can calculate the speed, though its primary, most common role is to supply precise position information (angle and rotation). Because tachometers measure speed directly and encoders can be used to derive speed from pulse rate, the common parameter they monitor is speed. Torque and temperature aren’t provided by these sensors, and while the encoder does track position, the tachometer does not, so speed is the shared parameter.