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Brians256 · 03-31-2003, 02:23 PM

I didn't mean to send you off on a red herring with the comment about the crystal.

Basically, I was referencing the "chip" used by computers (and many other electronic devices) to keep time. A crystal resonates at a given frequency based upon how it is cut, but it depends upon a precise pair of capacitors on each side to keep the electronic ticks happening. So, adding anything to a crystal circuit can make it not work. Not that it matters to what you are doing!

Now, as for adding a capacitor to make it start up... that really shouldn't be necessary unless you are really downrating the fan speeds (i.e. less than 30% duty cycle). My circuit worked well down to about 30% speed on my fans, which was far below the (to my ears) silence threshold.

Good luck!

03-31-2003, 02:23 PM	#13
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	I didn't mean to send you off on a red herring with the comment about the crystal. Basically, I was referencing the "chip" used by computers (and many other electronic devices) to keep time. A crystal resonates at a given frequency based upon how it is cut, but it depends upon a precise pair of capacitors on each side to keep the electronic ticks happening. So, adding anything to a crystal circuit can make it not work. Not that it matters to what you are doing! Now, as for adding a capacitor to make it start up... that really shouldn't be necessary unless you are really downrating the fan speeds (i.e. less than 30% duty cycle). My circuit worked well down to about 30% speed on my fans, which was far below the (to my ears) silence threshold. Good luck!