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Adaptor For Christmas Lights

Discussion in 'Electrics UK' started by DazJWood, 11 Jan 2010.

  1. olly_k

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    why can he not use a dc adapter? I would suggest an ac adapter was used because dc is an unnecessary expense for this design.

    Please at least offer an explanation before using derogatory smiley's :(

    Just to add volts may be a little high so a lower setting or series resistor may be nescesary but apart from that I can't see any other problem!
     
  2. ColJack

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    because the lable for the lights asks for a 4.5V AC 50hz supply..

    do you stick leaded in your diesel car?
     
  3. DazJWood

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    Does anyone know of the best place to buy a AC adaptor that would power these?

    Thanks,

    Daz
     
  4. dannyboi2003

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    Daz, I might have one in my box of spare transformers. I'll have a look the weekend and let you know, if you find one no probs but i'll have a look when im up the attic anyway. ATB - Dan.
     
  5. ban-all-sheds

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    Click
     
  6. DazJWood

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    Thanks for your help!

    I am well aware of google thanks and have already searched on there to find them at 3 times the price I bought the lights at. I asked because I thought some of the experts may have been able to recommend a specific outlet.
     
  7. olly_k

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    You will NOT get an ac adapter like this AFAIK there is no market for such an output. You could build your own but that IMO is beyond casual DIY. You can ignore my advice but you can send the lights to me if you like I will connect them up to DC ;)

    Seriously the person who said not to connect to dc has not given a good reason the only problem maybe that 4.5v dc might be too higher voltage depending whether there are inline resistors or not. Also as I said if leds are alternatively connected in reverse polarity only half would work, which half would depend on the polarity of the connection.
    There may be something more exotic in that plastic box but no harm will come by hooking DC especially if you start off at 3v or so, which most adustable adaptors allow.
    Now if you would have read my earlier post you would be able to tell us more and we might be a little 'brighter' for it. However, perhaps what you need to hear is this - in the future tell your wife to be more wary before buying incomplete electrical items from B&Q ;)
     
  8. ban-all-sheds

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    I wonder why Maplin sell them then...

    [​IMG]
     
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  9. ColJack

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    I have given a perfectly reasonable explanation..
    it says AC on the lights so you give it AC.. :rolleyes:

    for all we know that little box does nothing but rectify it to DC.. in which case yes a DC supply wouldn't hurt it, but it could also be for flashing the lights and use the 50hz as a clock to step through the flash patterns..
     
  10. ban-all-sheds

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    I wonder if the OP has an oscilloscope?


    You'd need to allow for the difference between P-P and RMS voltage when selecting your DC adapter.....
     
  11. olly_k

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    Hmm, which would mean that a capacitor would be required to isolate the part that counts pulses so dc would have absolutely no effect. Also there would have to be at least a half wave rectifier to convert to dc for the extra circuitry. Anyway this is a method used maybe minimum 30 years ago to keep the time on a vcr or timebase in a telly these days heck of a lot cheaper to use a microprocessor which again works off dc. AC is specified because dc is not required and would be a considerable expense in mass manufacture.

    Seems BAS has found the answer so hats off to him :D Oh but to answer the other question bas I did suggest OP select 3v instead of 4.5V however I bet if you measure the AC voltage of the supplied transformer even under load it will be more than 4.5V (RMS) ;)
     
  12. ban-all-sheds

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  13. plugwash

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    sneaky
     
  14. ban-all-sheds

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  15. dannyboi2003

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    Hey Daz, I had a look in my box of spares over the weekend and i dont have any suitable transformers sorry. The one bas linked to from maplins should do the job for you tho!
     
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