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Running an LED off a 120v wall outlet

CocaCola

Apr 7, 2012
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What you are seeing in the microsope is a microsopic part of the beam coming out of the light

And thus the reason an LEDs has an advantage in this application as the light is already focused... We don't care about the total amount of lumens as a vast majority of it is waste, because like you said where are only getting a microscopic slice of that light...
 

raultiger

Jun 12, 2012
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Ok hahaha i guess ill try some lower power stuff first. What power would you recommend?
 

CocaCola

Apr 7, 2012
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Ok hahaha i guess ill try some lower power stuff first. What power would you recommend?

I would likely just pickup several of the higher mcd 5mm white LEDs, you can always dim them... And once I got them I would try one, see how it work, then bundle two together and see how it goes, 3, 4, 5 or even a bundle of 10...

And another thing to consider, say you find that 10, 100,000mcd 5mm leds work well, but the bundle of 10 is too large or you wish it was a little more but you are out of space, you can drop down and use 3mm LEDs at or near the same rating...

Once you get into those high flux ones (like you linked) you have to deal with the heat and the fact most want a constant current source... Not a huge obstacle but it would need to be addressed, and those LEDs are crazy bright...
 

raultiger

Jun 12, 2012
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ok ill get several of those led and test to see what works. One last question (of course i have more to ask:D), if i go for the multiple LED approach, it wont be easily replaceable for the next owner. How long would these diodes last? or is there a way that they would be easily replaceable?
thanks
 

CocaCola

Apr 7, 2012
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How long would these diodes last? or is there a way that they would be easily replaceable?

They should last in excess of 10,000 hours without issue, likely much longer... Estimates into or around 100,000 hours are not uncommon, but their intensity will diminish over time... By then, there will likely be a better replacement option ;)
 
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KJ6EAD

Aug 13, 2011
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If you leave the thing on all day and night for the next 11 years, half of the LEDs may fail and all will be dimmer than when they were new. :) This is why you rarely see an LED socketed.
 

Iron Will

Jun 11, 2012
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Was this in reply to me? If so can you elaborate?
you said LEDs in series cannot rely on a single resistor? Is that Sarcasm i sense? :D

I guess the battery approach could work but doesn't it depend on how long you leave the LED on?
I like Coke's idea regarding the wire extension.
you already know what voltage you need, whether it is a wall wart or battery, it is still DC.
 

CocaCola

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you said LEDs in series cannot rely on a single resistor? Is that Sarcasm i sense? :D

No I said "Like LEDs can be run in series with a single resistor..." in reply to you stating "It's just if you use more than one LED, you will need more than one Resistor."

you already know what voltage you need, whether it is a wall wart or battery, it is still DC.

You really won't know what voltage is best until you finalize the layout of the LEDs, depending on your series/parallel choices it can be all over the place...
 

BobK

Jan 5, 2010
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And thus the reason an LEDs has an advantage in this application as the light is already focused... We don't care about the total amount of lumens as a vast majority of it is waste, because like you said where are only getting a microscopic slice of that light...
But the high quality lights have a 20W halogen with reflectors and columnators, which makes them at least as directional as an LED. This is why I think you need reasonable high power especially at high magnifcations. Do a search on for microscope illumination products, you will see what I am talking about, they are not selling 5mm low power LEDs for this purpose.

I will take your bet about a single low power LED being too bright for microscope illumination. Just make sure you go to at least 400X when you test it.

Bob
 

inlineskater

Jun 15, 2012
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I use a USB LED night light. I picked it up for $2.00 - I've had it for 5 years now and it still runs like new. Very intense and has a flexible neck. My microscope and this is a perfect match.
 

Mongrel Shark

Jun 6, 2012
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Not too bright!.... Bright light focused on your retina with quality optics..... Probably not the greatest idea.... I'd be finding out exactly what MCD, Lumen, or LUX was made by the original light and not exceed that value. Or at least guesstimate really well. I'm sure I was warned about using a microscope with bright light and say white paper or a mirror under the lens.


Could I also suggest multiple colors. And maybe some light filters for one of the lenses. Think how handy it could be to be able to throw a bit of extra UV or infared, Or just normal spectrum green yellow red blue etc... I can think of many things a person might want to look at under a microscope that would look different or behave different for different light colors...

If you got the mix right. All on at once would appear pretty close to real sun with the variety of LEDs around now...
 

Aniruddh

Jun 13, 2012
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if you are using 2*2 matrix, two raw of two LED each, then simply connnect 470 Ohm resistor and the 9 V battery in series to the LED matrix.
 
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