Which device provides feedback on rotation or position to enable speed and position control?

• A. Battery
• B. Motor controller
• C. Encoder
• D. Gearbox

Answer: (C)

Providing feedback about rotation or position lets a controller regulate speed and position. An encoder attached to the rotating part measures how far and how fast it has turned and converts that motion into electrical signals. The motor controller uses this feedback to compare actual motion with the desired motion and adjust power to reach the target, enabling precise speed and position control. Encoders come in two main kinds: incremental encoders, which output pulses proportional to movement, and absolute encoders, which give a definite position value. A battery is just a power source, a gearbox changes speed and torque mechanically, and a motor controller can drive the motor but relies on feedback from an encoder to know how the system is actually moving.