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Thoughts on DIY LED (3)

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  • Thoughts on DIY LED (3)

    Oh! In my last posting, I cut things short a little bit. Let's resume.

    1) The calculated resistor for an 18 V string was 2R @ 0,5W, so, a 1W resistor would be advisable. Always over-kill the specs. It won't draw more current nor will it make the little wheel in the hydro box run faster. It just means that the resistor has a thicker skin.

    2) So if I draw 500mA from my salvaged laptop PSU with one string, it also means that I can plug 10 such strings to the same 5A PSU. But as I always say, do not try to exceed 7 or 8. Always over-kill by measure of precaution.

    3) And always remember that cool white and warm white LEDs are basically blue LEDs and that they lend a fair amount of blue light. So do not try to put more than one pure blue LED. Even so that in order to boost your voltage to 18V, maybe, adding two more red instead of an extra white should work well also. You tell me. I certainly don't know.

    4) All of that, if you understand the calculations well, would also work with a beefy 12VDC class III wall wart. Just reduce your strings below 12V and calculate the resistor accordingly.

    5) You do not have to string them the way I said. Making a mainly blue string or a mainly red string would work just as well. Thus giving you the oportunity to switch from a warmer or a colder color.

    Next posting, heat dissipation. OMG! I almost flunked my course on that topic. It is not that simple to master. But, rule of thumb, always aim for luke warm heat sinks. This way, you won't have to make the calculations!

    So long...
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