What is a Servo?

A Servo is a small device that incorporates a two wire DC motor, a gear train, a potentiometer, an integrated circuit, and an output shaft. Of the three wires that stick out from the motor casing, one is for power, one is for ground, and one is a control input line. The shaft of the servo can be positioned to specific angular positions by sending a coded signal. As long as the coded signal exists on the input line, the servo will maintain the angular position of the shaft. If the coded signal changes, then the angular position of the shaft changes.

A very common use of servos is in Radio Controlled models like cars, airplanes, robots, and puppets. They are also used in powerful heavy-duty sail boats. Servos are rated for Speed and Torque. Normally there are two servos of the same kind, one geared towards speed (sacrificing torque), and the other towards torque (sacrificing speed).

Servos come in different sizes but use similar control schemes and are extremely useful in robotics. The motors are small and are extremely powerful for their size. It also draws power proportional to the mechanical load. A lightly loaded servo, therefore, doesn't consume much energy.