Note: There are a handful ofother position sensors such asencoders and resolvers, but thevariable resistor is common.
The blue area is an interesting partof the servo
This is the feedback (closed) loopthat is always checking itself.
Where are servos used?Remote-controlled or radio-controlled toy cars, robots and airplanes, industrial applications, robotics, in- line manufacturing, pharmaceutics, and food services
Advantages among different servo motors High output power relative to motor size and weight. Closed loop system-It gives itself feedback as to its positionor speed High efficiency. It can approach 90% at light loads. High torque to inertia ratio. It can rapidly accelerate loads. Has "reserve" power. 2-3 times continuous power for shortperiods. Has "reserve" torque. 5-10 times rated torque for shortperiods. Audibly quiet at high speeds. Resonance and vibration free operation.
Disadvantages among different servo motors Requires "tuning" to stabilize feedback loop. Motor "runs away" when something breaks. Safety circuitsare required. Peak torque is limited to a 1% duty cycle. Motor can be damaged by sustained overload. Bewildering choice of motors, encoders, and servodrives. Motor develops peak power at higher speeds. Gearingoften required. RC Servo motors have a limitation of movement unlesshacked. Usually cost more than a stepper motor