[sdiy] Retaining button state after power off?

Hugh Blemings hugh at blemings.org
Fri Jan 31 19:50:06 CET 2014

Hi Justin, All,

I find myself wondering if you could use a supercap or similar to keep 
the ripple counter powered for a while (weeks ?) after the main power 
was removed.

Judicious use of low Vf diodes could isolate Vcc for the CMOS components 
in question though I guess you may end up parasitically powering other 
bits of the system and/or with upset components that were seeing a 
voltage on one of their inputs while the power was off.

Anyway, a bit of armwaving $0.20 but since we've had latching relays I 
thought I'd throw another wild-ish idea in there :)


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