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SC8560 AM/FM clock radio 50Hz drifts

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by manoj.patil.1974, Dec 4, 2006.

  1. mvs sarma

    mvs sarma Well-Known Member

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    Hi,

    For LED display, it may not longer than a week i feel. perhaps mains trnsformer can remain to float the battery and tricklle charge while taking the real load of the clock. Battery can work during PF times. One thing remains that the battery requres reharsal of full discharge and recharge to sustain the battery.

    the compression can be done by ms paint, even if the pics were taken at 5Mpix as i was doing on my Kodak z730.
     
    Last edited: Jan 3, 2007
  2. ljcox

    ljcox Well-Known Member

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    The battery does not float. The normal arrangement is that there is a diode in series with the battery so it is only used when the power fails.
    Thanks. I fiddled with MS Paint but to no avail. I'll try again.
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    My cheap LED clocks use an ordinary battery for backup, not a rechargable battery. So a diode isolates the battery until the power fails, which hardly ever happens.
     
  4. dave

    Dave New Member

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  5. nura100

    nura100 Member

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    Hello Guys,

    iam using a normal PP3-9V Alkaline Battery for Back-up, during power failure the display is turned Off and only the Oscillator Section & the Clock IC get power thru the Back-up battery.

    when mains is present, rectified, smooth 9.5 Volts DC is available, this supply is used to turn on a N-channel mosfet which in turn connects the display circuit to Gnd, during Power Failure, the Mosfet is Off and so is the Display section.

    i tried using Rechargable Batt. but dropped the idea b'coz of charge & discharge issues.

    as many of you guessed it , i have used a lower resolution for image size in my digicam (640X350) other wise it would have been very difficult to post these pics.

    arun
     
  6. mvs sarma

    mvs sarma Well-Known Member

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    Hi,
    you try to load the .jpg file by open with by right clicking. then try to reduce the size of photo by stretch/skew button, reduce to say 60% both vertical and horizotal.
    repeat the process until you get the pic of the wanted size-- then save as filname_a.jpg
    if you see the properties of new file you will be satisfied of reduction.
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    But it doesn't keep the display running does it?.

    And I suspect mains reliability in Canada is probably a LOT better than India!.
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    My LED clocks use a lot of power for the display. The battery just keeps the counter running if the power fails.

    In Canada the electricity comes out of the ground and "grows on trees". Most of mine comes from the water-driven generators at Niagara Falls. The waterfall is never expected to quit.
     
  9. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Like I said, no display during battery backup - mines the same.

    Doesn't Niagra Falls feed New York as well?, it doesn't stop massive cascading power cuts there!.
     
  10. mvs sarma

    mvs sarma Well-Known Member

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    Hi, Audiguru and Nigel,

    the final version arrived at by Nura100 and manoj is powered completely by Bty and nOT bty standby. theereby the clock continues to work as standalone. Depending on ones own necessity, the design is modified. we can change societies but not overnight. one cant expect to reach UK,US and Canadian standards even with sicere attemps, the developing countires have to be stable and self suffiecent and we may have to encourage them towards standards. Perhpas you may appeciate, it takes time.

    Regards to both GURUs.
     
  11. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Yes, I understand that, that's why I was explaining to AudioGuru.
     
  12. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The developing countries have been developing for a very long time. Too long.

    Occasionally the electrical grid for most of North America has a blackout because Canada and United States have their grids joined together. Then protection breakers don't work properly and the whole system goes down.
    It happens so rarely that we celebrate when it does.
     
  13. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    India threw the Brits out too soon! - should have waited until we electrified the place!.

    Never happens in the UK - if anything happens the breakers seem to work fine. The city of Birmingham had a major outage one night last week - apparently a large sub station went BOOM!!! :D
     
  14. Hero999

    Hero999 Banned

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    Perhaps we should cease hold of Iraq, use the oil money to develop the country keeping a small amount of it for ourselvs as commision then return it back to the people when it's a modern civalised country.
     
  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    No disrespect to the Iraqi people, but a modern civilised country requires a modern civilised population!.

    The overwhelming reliance on primitive superstition (called religion!) really prevents this ever happening!.
     
  16. mvs sarma

    mvs sarma Well-Known Member

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    Hi,
    after the modification by nura100 and manoj.patil.1974 , these clocks don't have any more standby bty . ther power trafo is removed and replaced by a dc source and clocking and display drive is from a derived clock -- thus it is now standalone and with bty even for display. it was because, display drive from mains and counert input from derived clock did not solve the issue as you watched the posts. latest schematic should be without trafo. and without standby bty.
     
  17. ljcox

    ljcox Well-Known Member

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    It should be possible to retain the standby battery. It would require some circuitry to detect when the power fails and thus switch off the display so that only the oscillator and counters are running.
     
  18. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I don't think he wants a standby battery?, and I can see his point with such a potentially poor mains supply - run it permanently from a LARGE battery, and charge it when the mains happens to be on :D
     
  19. ljcox

    ljcox Well-Known Member

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    Thanks Sarma, I tried it this morning using MS Paint and it works very well.

    First I tried a 1.2 Mb photo to 10% and it compressed it to 40.8 kb.

    The quality degrades of course, but I expected that.

    I then tried a 40% reduction on a 1.18 Mb photo and it compressed it to 124 kb with quite acceptable quality.
     
  20. quad

    quad New Member

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    Manoj and Arun, Can you please post your final complete schematics? I want to modify sc8560 clock too to run off a crystal
     
  21. khathorzhe

    khathorzhe New Member

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    am/fm radio clock (sleepmode)

    Hiiiiiiii!!!!!... do you have an schematic diagram of am/fm radio clock(sleepmode).?

    plzzzzzzz!!!! can you tell me wer i can find the circuit.?

    thankzzzzzzzz!!!!
     

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