Hi,
does anyone know the Maximum PWM Freqency the Spark 4 can generate? I would like to controll a fan that needs 25KHz ! for maximum speed.
Will it damage anything in the spark in Long Term? (Should I bettet buy another fan?)
Thanks :)
Most PC fans spec a 25khz frequency, but can also be controlled with a lower frequency. The IO module only has fixed frequencies, 80Hz, 100Hz and 2kHz.
I assume you use a 4-wire PC fan with a PWM input, so you can leave power connected and control the speed with the PWM input? Then just try using 2 kHz.
You say 25khz for max speed, but that suggests that the speed is frequency controlled, which is probably not true. That’s not PWM.
Ah ok - as always you are right
Yes I am trying to use a 4 wire PC fan and I will try using 2kHz.
Should work - because after thinking a bit about your comment it came to me, that the the PWM „Simulates“ changing Voltage by changing duty cycles.
Was confused by the instructions of the fan… and after a day of work it was to much for me🤪.
Thank you Elco
For your super fast andere and helpful reply!
Works like a charm even with 200Hz PWM frequency - although bettet with 2000Hz. Thanks again 
1 Like