>
> BTW does the mains voltage not affect your design ? It can vary by
> +5/-5% usually, f.ex. due to increased load in a longer house feed
> line.


Mains voltage will definitely affect me.  My appliance uses resistive
heating, so the power (and temperature) will vary as the square of
the mains voltage.  My circuit uses linear components (resistors,
etc.) and the time varies linearly with mains voltage.  Extreme
variations in line voltage (105 down from 120) will cause really poor
behavior, but small variations (5%) will cause similar size
variations in performance.  The short answer is the timer will
compensate for line voltage a little bit, and this little bit is
within acceptable limits.
-- Lawrence Lile

 "If this were easy they'd have hired somebody else to do it."

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