M
Martin Brown
Increasingly home consumer electronics has an RTC built in to display
the time in some fashion. Ovens, microwaves, alarm clocks and teamakers
being obvious examples. Alas most of them do not survive even a couple
of seconds of mains interruption without resetting to midnight.
This is pretty ludicrous since the newer RTC chips draw under 1uA and
the older ones maybe 10uA including driving an LCD display.
For the cost of a capacitor and a diode to keep the RTC clock powered
for a few minutes of power outage all the devices have to be manually
reset to the correct time each time the powerline glitches. A 3300uF
capacitor ought to be good for nearly an hour or so down time.
At least a traditional mechanical mains powered alarm clock would only
be thrown by however long the power cut lasted. The modern ones are now
out by however long it was to midnight when the power briefly went off.
The powercut last night was 10s long an hour before midnight. Grrrr!
Regards,
Martin Brown
the time in some fashion. Ovens, microwaves, alarm clocks and teamakers
being obvious examples. Alas most of them do not survive even a couple
of seconds of mains interruption without resetting to midnight.
This is pretty ludicrous since the newer RTC chips draw under 1uA and
the older ones maybe 10uA including driving an LCD display.
For the cost of a capacitor and a diode to keep the RTC clock powered
for a few minutes of power outage all the devices have to be manually
reset to the correct time each time the powerline glitches. A 3300uF
capacitor ought to be good for nearly an hour or so down time.
At least a traditional mechanical mains powered alarm clock would only
be thrown by however long the power cut lasted. The modern ones are now
out by however long it was to midnight when the power briefly went off.
The powercut last night was 10s long an hour before midnight. Grrrr!
Regards,
Martin Brown