hey all, I've wired up a standard 555 timer, using two resistors, a capacitor and a diode to make a clock in order to feed a stepper motor controller. http://wolfstone.halloweenhost.com/TechBase/com555_555AnyDutyCycle.gif Its wired like the schematic above. My resistor values are the following: R1=4.66K, R2=13.560K,C=2.2uF. This should give me a calculated clock freq of 36Hz with a duty cycle of 25.6%. But, when I measure the frequency using my DMM, its rapidly fluctuating. For instance, it'll be 38 one moment, and then 36, then 24 or whatever value it wants to be, really! Its quite random. Looking at the stepper motor, it does not appear to slow down or speed up, its rotating at a constant speed. What could be the cause of this rapidly fluctuating frequency? It only occurs when the controller is attached to the driver and the motor is running. Any advice would be massively appreciated.