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ahonda55
Apprentice
Egypt
57 Posts |
 Posted - Dec 30 2008 : 5:31:50 PM
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Hello and happy new year :)
I have a transformer, like the traditional wall mounted one, produces 3~12v DC
And i have a digital clock with LCD you know, the kind of clocks which places on the office top, a cheap one, it runs on 2xAA betteries.
When i connected the transformer (adjusted on 3v) to the clock nothing happened.
What do i need to convert a cheap digital wrist clock or office clock to run on transformer ??
Greetings
Ahmed |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Dec 30 2008 : 6:10:02 PM
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Maybe you connected an AC transformer (3VAC) instead of an AC-DC adapter.
Maybe you used 3VDC with backwards polarity.
Maybe the adapter cannot produce enough current, but an LCD clock uses an extremely low current.
Maybe the adapter has an output of 3VDC at its rated current but a much higher voltage when the current is low and its high voltage blew up the clock. |
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ahonda55
Apprentice
Egypt
57 Posts |
Posted - Dec 31 2008 : 4:47:38 PM
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Thanks a lot
it is 3v DC, the transformer is rated 500mA max.
today i have used a computer power supply, the 5v line, the clock worked, but, got hot  , so i decided to make a voltage devider, got a regulaor 7806, and two resistors to form a voltage devider, and checked the output voltage with my voltmeter, it was 4.5v, from the 12v input line, bu the clock still doesn't want to work.
it still work from the bateries.
so 2x AA batteries = working ok
Pc powersupply 5v = working almost ok.
PC powersupply 12v + 7806 regulator + voltage devider = 4.5v = Not working.
so what !! |
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Wrist Clock on Transformer ?? "How"
