| Inside the servo motor, there is a built-in 'DC' | | | | 5V (using voltage regulator). Amount of voltage |
| (direct current) motor with gearing and feedback | | | | depends on applications needed. 5V voltage is |
| control loop circuitry. This gearing enables speed | | | | enough to drive torque to perform useful motions. |
| reduction and high torque production. The control | | | | Commonly, servo motors are powered by smaller |
| loop circuitry is responsible for its high precision | | | | batteries like Nickel Cadmium ('NiCd') or |
| control. This reduces the need for additional motor | | | | Nickel-Metal Hydride ('NiMh') or even the latest; |
| driver circuit. Servos or servo motors in this | | | | Lithium Polymer ('LiPo'). |
| project rotate from approximately 90 to 180 | | | | External power supply delivers power the motors. |
| degrees range. Note that servos can be modified | | | | Power supply to micro controller circuit board |
| to rotate continuously (360 degrees). | | | | should be separate, and powered by computer |
| Wiring of the servo is simple; red wire is for 'DC' | | | | universal serial bus 'USB' (Universal Serial Bus) |
| +5V, black wire connects to 'GND' (ground) and | | | | connection. Both power supplies ground |
| white wire for signal (where 'PWM' is sent to the | | | | connections must be in common to each other, |
| motor). The white wire is responsible for | | | | for the servo motors to function properly. |
| controlling degree of rotations. | | | | A pulse of 1.5milisecond (ms) will always set servo |
| Voltages from 4.8V to 6.0V can be used to | | | | to its neutral position (90 degrees). A minimum |
| power a servo. Higher voltage rating (6.0V) | | | | pulse of 1ms sets it to turn 90 degrees left. A |
| produces higher torque. But for safety | | | | maximum pulse of 2ms will bring it to the 180 |
| conservation, a regulated 'DC' voltage of 5V is | | | | degrees position. These pulse width or 'PWM' |
| used. This way, servo motors would not exceed | | | | (pulse width modulation) can vary, depending on |
| its maximum voltage limit. | | | | programming of micro controller. For example, |
| The servo motors are usually powered by | | | | servo will turn to approximately 45 degrees if |
| batteries. This power source is then regulated to | | | | given a 'PWM' of 1.25ms. |