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Can I wire an LED directly to an AC DC power supply? Answered

Hi everyone, 
This is my first time posting on Instructables.com so please forgive my noobness!

Here is my issue:
I have an idea of a really nice lamp to make for my girlfriend using a single 8W High-powered LED (http://shop.rabtron.co.za/catalog/high-power-white-p-7492.html) powered with a 12V 500mA AC DC Adapter (http://shop.rabtron.co.za/catalog/adaptor-500ma-fixed-p-6289.html)

First off, is this possible? If not, why not and what is the correct way to go about it?
Secondly, will this LED be bright enough for a desk lamp? 

Thanks all! Happy instructing!

Discussions

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Shampoo1014

3 years ago

Thanks everyone for your input, I'm glad I asked here. I will find another way to do this thing. (Was basically wanting to put an LED inside an empty animal vertebra bone without being able to actually see the light, for a lamp).

Cheers :)

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Shampoo1014

3 years ago

Thanks for your reply, I actually don't know much about high powered LEDs which I why I was asking some advice here. I did do a bit of Googling but I found very little in relation to using adapters to power them.

Also, if the PSU only gave 500mA, would the LED not even turn on? Surely it would just be dimmer? What vital components have I missed? Or would this need to be a system with capacitors and what not?

What can you suggest?

Thanks :)

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gmoonShampoo1014

Reply 3 years ago

Depending on the PS, drawing more current than it is spec'd to supply probably won't work (it will shut down if it has overload protection). Or it might work intermittently (BIG warning flag!). It could conceivably even be dangerous, although safeguards on a modern switching supply should prevent major problems.

Modern power supplies aren't like an old-school transformer-based PS...they don't have a "fudge" zone like analog devices. They either work as intended or they don't. IF you're pushing the specs, you're trusting the manufacturer built it right (look at those current hoverboard fires for worst-case) and you're breaking the common-sense rules...

..which is what Downunder35m is trying to tell you...

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Downunder35mShampoo1014

Reply 3 years ago

As I said you need proper heatsinks for the diodes to start with.
For each diode a suitable constant current driver.
A PSU that provides at least 25% more power than what the combined LED's need.
Might be easier to just buy a lamp !?
Using your little power supply is like towing a 2T caravan with an old VW bug - it will work but after a short the motor is toast.

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Downunder35m

3 years ago

1. Check the specs of what you select and you might notice a 500mA supply won't be able to provide 600mA.
2. Do you actually have any knowlwedge at all about high power LED's as you missed the most vital components?

To answer your questions:
NO
Read it up, plenty of topics and Ibles here, otherwise use Google.
No idea as I don't know your definition of bright enoug - again: What do you know about high power LED's and Lumens?