EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: tony359 on September 06, 2022, 07:26:11 pm
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Hello all,
I have a cheap fan controller board which sets the speed of the fan based on the temperature. Temperature delta are set and can be chosen via dip-switch. I would like to change the range of intervention as I need something more 25-35 degrees and the lowest range I can select is 35-45.
The circuit has been reverse-engineered here: https://www.electroschematics.com/fan-speed-controller/ (https://www.electroschematics.com/fan-speed-controller/)
There is an NTC sensor which is wired like the attached.
I found that replacing those two 103 (10K) resistors with a 12K one, the intervention range lowers so that the fan starts speeding up slightly at room temperature. Is that the correct approach? Can I add a resistor in series/parallel to the NTC instead to achieve the same thing? Maybe a variable one?
Thank you!