Digital Clock Speeding Up (ie Gaining Time)

Hi guys.

I had a typical digital alarm clock for a few years. I noticed it started to report the time a few minutes fast. If I reset it the time would still go forward.

I'm estimating it gains around a minute a week. This doesn't sound like much, but in 6 months the clock is half an hour ahead of the correct time.

I thought the clock might be playing up because it is plugged in with a dozen other electrical devices (computer, home theatre etc). To confirm I plugged it into another socket on it's own in another room. The problem persisted so I threw it out.

I got a new clock, and after a few months it is 20 mins ahead!

Does anybody know the cause of this problem?

Thanx 4 looking.

Reply to
ghostgunna
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Most mains powered clocks derive their time form the 50Hz mains which is very accurate over a long time period. So your clocks are most likely picking up noise on the mains that is causing missing pulses or some such problem. Try adding a good mains filter to the clock, or just get a clock that does not rely on the 50Hz mains (usually the battery powered type).

Dave :)

Reply to
David L. Jones

"David L. Jones" wrote

Most mains powered clocks derive their time form the 50Hz mains which is very accurate over a long time period. So your clocks are most likely picking up noise on the mains that is causing missing pulses or some such problem.

****What??? The clock is supposedly gaining time,not losing it! If it is missing "pulses" it will lose time!

Brian Goldsmith

Reply to
Brian Goldsmith.

Oops, I meant "extra" pulses.

Dave :)

Reply to
David L. Jones
** Groper Alert !

** Likely the clock is not being powered by the AC mains supply on a 24 / 7 basis.

During the unpowered periods, the internal ( battery powered) time base oscillator takes over - and it runs a tad fast.

Maybe the missus uses it power outlet for her vacuum cleaner or her steam iron or her ............

....... Phil

Reply to
Phil Allison

On 17 Oct 2006 01:12:55 -0700, snipped-for-privacy@mail.tpg.com.au put finger to keyboard and composed:

There was a clock that featured in a thread at sci.electronics.repair some years ago that was affected by off-peak pulses or "remote-reading electrical power meters" or similar signals.

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- Franc Zabkar

--
Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

Thanx 2 everyone who replied.

When you say battery powered clocks, do you mean regular alkaline batteries? If so, wouldn't battery powered clocks lose time when the battery goes flat? And, wouldn't they go flat often?

I don't think my clock has a battery at all. Whenever power is lost the clock is reset to 12:00.

I noticed the clock on my microwave keeps the right time. Does that sound right if there is a problem with the power here?

Is this the type of filter I should be looking at getting?

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Reply to
ghostgunna

** No one mentioned *any* such thing.

You asinine Google Groups WANKER !!

...... . Phil

Reply to
Phil Allison

No, an LCD display clock should last for years, just like a digtial watch. Something like this:

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That means it most likely has better designed circuitry (filtering) that gets pulses from the 50Hz mains. With your other clocks you have just been unlucky with a poorly designed product - twice.

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None of them seem to have the word "filter" in them, just "surge protection", that is different. Not that a filter is guaranteed to work anyway, cheaper to simply buy an LCD digital clock.

Dave :)

Reply to
David L. Jones

I mentioned it Phil, in my first post. Dave :)

Reply to
David L. Jones

Thanx 4 your help Dave.

I'll get myself an LCD clock.

David L. J> > Thanx 2 everyone who replied.

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Reply to
ghostgunna

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