Servomotors (not to be confused with stepper motors, which we will discuss in Chapter 10) combine a small DC motor, some gears, and a control circuit including a variable resistor to be able to position the arm of a servo at a certain angle.
This makes them really handy for projects where you want to make something move fairly quickly and relatively precisely.
While you can get continuous servos that can rotate continuously, most servomotors (or just servos) can only rotate through about 180°. They are often used in remote control vehicles to control steering, or the angles of surfaces on an R/C airplane. Figure 9-1 shows two different sizes of servo.
The servo on ...