servo
SER-voh
/ˈsɜː.vəʊ/
An automatic device (such as a motor) that uses error-sensing feedback to correct its performance or position.
Short for servomotor or servomechanism. It is characterized by its closed-loop control system, meaning it constantly checks its actual position against the target position and self-corrects.
The story behind the word. Coined in French as servo-moteur by the French engineer Joseph Farcot in 1868. He chose the Latin root servus (meaning 'slave' or 'servant') because the motor acted as an obedient servant, instantly correcting its actions to follow the master control signals.
Word relationships
- servomotor: Servomotor is the full technical term, while servo is the widely accepted industry shorthand.
- feedback motor: Feedback motor is a descriptive term, whereas servo is the precise engineering classification.
Commonly confused with
- stepper motor: A stepper motor moves in precise, open-loop steps without checking its final position, whereas a servo uses closed-loop feedback to constantly verify and adjust its position.
Word family
- servomechanism (noun): An automatic device for controlling large amounts of power by using small amounts of power.
Collocations
- servo motor
- servo mechanism
- digital servo
- servo control
Example sentences
- "The drone's camera gimbal is stabilized by three miniature servos that react to sudden movements." A guide to building hobbyist drones.
- "The precision of the CNC machine depends on high-torque servos driving the cutting head." A description of industrial machinery.
Memory hook
A servo acts like a faithful 'servant' that constantly double-checks if it did exactly what you asked. Servo = Obedient servant motor.
When not to use
Do not use to describe simple DC motors that spin continuously without any feedback or position control.
Fun facts
- Servos are what allow remote-controlled airplanes to move their wing flaps with extreme precision in response to a pilot's joystick movements.
Related words
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