Wiring a Hobby Servo

Hobby servo motors have 3 wires:

The Fritzing diagram for this simple connection is shown below:

A Micro-Servo Attached to an Arduino

Note! The control line of the servo is attached to Pin 9. This pin, or pin 10,
are the preferred I/O control lines for servos, because the Servo library
that will be used for this example disables PWM on those pins anyway.
So, by using Pin 9 (or Pin 10) you don’t lose any functionality that you would
otherwise have had.

Also note that the power for the servo is provided by an external battery. The reason
is that the servo (especially, servos turning a big load, or large (so-called “1/4 scale” or
“Mega”-scale servos) will draw much more current than can safely be delivered through
the I/O pins of the Arduino.

The Arduino itself is assumed to be powered through its USB port or through another
external battery.

ESSENTIAL: The Arduino, the servo, and the external battery MUST be connected to
the same GND bus. In short: