Normal DC motors just require power supply(+V and GND) and are controlled by switching it ON/OFF or by varying the amount of power supplied to it but in case of servo motors we generally need a microcontroller to control them since it needs a special signal along with the normal power supply(+V,GND and SIG). This circuit will show how to control a servo without using a microcontroller. The circuit uses a 555 Timer IC which is very cheap when compared to a microcontroller and also which doesn’t require programming. The 555 IC is configured in Astable Mode to generate the “Special Signal” for the servo motor to work. First let us understand that signal. Here the special signal is nothing but a Pulse Width Modulated signal usually with a frequency of 50Hz (i.e. a Time Period of 20msec) or 25Hz (Time Period 40msec).