I'm looking for a simple way to control the duty cycle of a 555 that will eventually drive a 12VDC, 400mA Computer fan based of the ambient temperature. I thought of the LM34, but the output is a temperature to voltage relationship. A thermistor might work, but I am a am stumbling on how to setup the 555 to accomplish a wide range of duty cycle. I want it to reach ~100% duty cycle but am not sure on how low the duty cycle will be needed to keep the fan spinning yet. I also want some sort of Hysteresis as I do not want the fan turning on/off all the time.
Any idea's on how to setup the 555 for this sort of arrangement?
Thanks
Any idea's on how to setup the 555 for this sort of arrangement?
Thanks