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Thread: small sealed 12VAC to 12VDC package

  1. #1

    Default small sealed 12VAC to 12VDC package

    I want to use some cheap LED strings for a landscape application. My current landscape xfmr puts out 12VAC (actually near 14VAC to be accurate). Does anyone know of a small, 12AC to 12DC converter, sealed so outdoor use wouldn't be an issue?

  2. #2
    Flashaholic* lolzertank's Avatar
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    Default Re: small sealed 12VAC to 12VDC package

    Four diodes or a bridge rectifier and a capacitor work well enough.
    Awesome! I just got the Luxoulree Z4 bin XD-Q! Wait... are you saying they released the Z5 bin the day after I bought it?

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    Default Re: small sealed 12VAC to 12VDC package

    Besides a full-wave bridge and filter cap, some sort of circuit to regulate LED current is a must. You can even go with a simple resistor if it's only a few low-power LEDs.

  4. #4

    Default Re: small sealed 12VAC to 12VDC package

    Thanks, so is there a pre-packaged package that is ready made to do this?

    If not, what regulator (and surrounding circuit) should I build? Can I encase that circuit in epoxy or moldable plastic or something so water won't infiltrate?

    Tome

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    Default Re: small sealed 12VAC to 12VDC package

    Hi,
    I made a lamp for a mechanic friend of mine about 12 months ago using the http://www.dealextreme.com/details.dx/sku.13555 driver. I potted it in epoxy resin to protect it from the elements. It's been used/abused and left outside ever since and still works
    Maybe a good start?

    Paul.

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    Flashaholic* znomit's Avatar
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    Default Re: small sealed 12VAC to 12VDC package

    AC buckpuck?

  7. #7

    Default Re: small sealed 12VAC to 12VDC package

    Quote Originally Posted by znomit View Post
    AC buckpuck?
    Now you're talkin' (I think)

    One of these: http://www.luxeonstar.com/buckpuck-3...leads-p-21.php

    So, if I read that right, I can put 12VAC into it, and can drive a pile of LEDs. However, the output voltage claims 32VDC, won't that fry a string that usually operates at 12VDC?

    Tome

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    Default Re: small sealed 12VAC to 12VDC package

    Quote Originally Posted by tome9999 View Post
    So, if I read that right, I can put 12VAC into it, and can drive a pile of LEDs. However, the output voltage claims 32VDC, won't that fry a string that usually operates at 12VDC?
    32VDC is the maximum DC input voltage. As stated on the link:

    350mA true constant current output regardless of the number of LEDs connected to the driver

    So this would work fine whether you connected it to one LED or several in series.

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    Default Re: small sealed 12VAC to 12VDC package

    But it is a buck driver so the input voltage HAS to be more than the output voltage.

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    Default Re: small sealed 12VAC to 12VDC package

    Quote Originally Posted by spencer View Post
    But it is a buck driver so the input voltage HAS to be more than the output voltage.
    Yes, that's definitely true. If the input is 5VDC then you can only run 1 LED. If it's 32 VDC then you can probably run 9 LEDs, possibly even 10 if they have a low Vf.

  11. #11
    Flashaholic* znomit's Avatar
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    Default Re: small sealed 12VAC to 12VDC package

    I haven't been through the AC datasheet but the DC needs about 1-2V overhead.
    So for the OP this would mean 14V would drive what 12V is driving now.... assuming the current setup is just LEDs (cheap LED strings... could be a few things), if its a string with a built in driver who know if it will work or not.

  12. #12

    Default Re: small sealed 12VAC to 12VDC package

    Quote Originally Posted by znomit View Post
    I haven't been through the AC datasheet but the DC needs about 1-2V overhead.
    So for the OP this would mean 14V would drive what 12V is driving now.... assuming the current setup is just LEDs (cheap LED strings... could be a few things), if its a string with a built in driver who know if it will work or not.
    I was thinking of buying a cheap xmas light string of led lights and cutting off the AC plug and voltage converter they have (or at least the ones I saw had) and driving the LEDs directly. I admit I don't know the LED specs but did see some 12VDC lights here:
    http://www.imaginarycolours.com/Merc...oduct_Count=13

    That I figured might be similar...
    Tome

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