[NLRS] stable audio oscillator?

[Dr. Gerald N. Johnson, electrical engineer]

Start out with a few MHz crystal and a CD4040. IIRC it has oscillator
built in plus a lot of decades of divider. Computer crystals are
available that will handily divide down to nice audio frequencies. You
may need to create a synchronous fan rather than the DC motor (probably
a brushless motor with AC drive inverted from DC) for the chopper.
Ordinary computer crystals should hold 10 ppm for any practical time
period (seconds to years).

I doubt the best 555 with the best components will hold to your 100
milliHz per minute.

73, Jerry, K0CQ
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