555 PWM

This is a 555 Timer circuit used to control a servo motor. Adjusting the potentiometer should change the duty cycle of the control signal sent to the servo. To adjust the position of the potentiometer, tap/click on the % parameter and use the slider to adjust the value. Source: The Robot Builder's Bonanza: http://www.robotoid.com/appnotes/circuits-servo-control-with-555-timer.html