On Thu, Jan 17, 2019 at 11:18 AM, Albert Peter wrote:

IMHO it is better to start with a capable quiet fan that does not require more circuitry.  It may cost a bit more, but is a simpler solution.

I totally agree with Al.  I have this fan https://www.digikey.com/product-detail/en/sunon-fans/HA60251V4-1000U-A99/259-1793-ND/ running arm's length away from me in a µBITX in an EF-01 enclosure on my desk.  It is so quiet I sometimes have to check that it is still working.
 
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