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TahmidKhan123
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Watt Calculation to Make a Specific LED Light

12/02/2019 11:12 AM

How much watt require to get following specified LED light? How to calculate?

Specification:

430-490 nm (460 nm at peak +/- 10 nm) with specification of an average irradiance of at least 30 μW / cm² / nm but not over 60 μW / cm² / nm. Hight from Surface app 1.5 feet.
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PWSlack
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#1

Re: Watt calculation to make a specific LED light.

12/02/2019 11:19 AM

One might test to find it out. Then one will have a formula that is proprietary, setting the organisation ahead of its competitors.

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TahmidKhan123
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#2
In reply to #1

Re: Watt calculation to make a specific LED light.

12/02/2019 11:25 AM

So no formula till now or calculation method for that?
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PWSlack
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#3
In reply to #2

Re: Watt calculation to make a specific LED light.

12/02/2019 11:32 AM

Why not design one (rhetorical question - NNTR)?

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SolarEagle
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#4

Re: Watt Calculation to Make a Specific LED Light

12/02/2019 12:26 PM

https://www.rapidtables.com/calc/light/lux-to-watt-calculator.html

https://www.translatorscafe.com/unit-converter/en-US/illumination/1-11/

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lyn
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#5

Re: Watt Calculation to Make a Specific LED Light

12/02/2019 12:34 PM

Some examples:

M430L4

430 nm (Violet)

490 mW / 600 mW15 nm35.3 µW/mm2500 mA3.8 V22°DC2200, LEDD1B, DC4100i, or DC4104i

M450LP1

450 nm
(Royal Blue)

1850 mW / 2100 mW18 nm35.6 µW/mm22000 mA3.5 V120°DC2200

M455L4

455 nm
(Royal Blue)

1150 mW / 1445 mW18 nm32 µW/mm21000 mA3.25 V80°DC2200, LEDD1B, DC4100i, or DC4104i

M470L4

470 nm (Blue)

760 mW / 965 mW26 nm19.9 µW/mm21000 mA3.2 V80°
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redfred
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#6

Re: Watt Calculation to Make a Specific LED Light

12/02/2019 12:45 PM

Light level units are not watts. A watt is nominally for the electric power applied to the illuminator. The SI unit for light levels lumen. Therefore the efficiency of the LED in converting watts to lumens (and how those watts are measured) must be known. Also, the units you proffer for light output are incorrect. There are a number of other light measuring units depending on what and how one is applying light. Here you will find a good introductory guide.

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SolarEagle
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#7
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Re: Watt Calculation to Make a Specific LED Light

12/02/2019 1:29 PM

The beam angle is also important...

The tighter the beam angle the more lumens per square meter but the less area covered...

..."Illuminance (lux): Illuminance is a measurement of the light intensity at any point. The light intensity drops exponentially the further away you get from the source (distance).

Luminous Flux (Lm): The luminous flux is a measure of the total light output from a source. For example, a 1 candela light source will product 1 lumen per square meter at the distance of 1 meter.

Beam Angle: The beam angle is the angle of radiation for a light source. For example a beam angle on 30 degrees means the light has a shape of a cone and its borders form a 15 degree angle with the center axis. A change in the beam angle affects the luminous intensity (lux) of a light source but not the luminous flux (Lumens)."...

https://ledstuff.co.nz/calculators

..."One lux (1 lux) is defined as being equivalent to one lumen spread over an area of one square metre. ... So 1,000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance level of 1000 lux."...

https://greenbusinesslight.com/resources/lighting-lux-lumens-watts/

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#8

Re: Watt Calculation to Make a Specific LED Light

12/03/2019 2:53 AM

I can't believe that not one of my esteemed colleagues has asked the most basic question: "Where is the rest of the specification?". If there is no more to the specification, don't buy it because you don't know its capability. Simple as that.

If however, you have only given YOUR INTERPRETATION of the specification, don't expect any decent answer at all until you give the complete, unabridged specification FROM THE MANUFACTURER!

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#9

Re: Watt Calculation to Make a Specific LED Light

12/03/2019 3:59 AM

Surely the parameters for a blue LED of 5mm diameter of 3.3V and forward current of max 30mA would set the W value for the led of 0.099W.

Go above 30mA and you end up frying the LED or is this not your question?

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TahmidKhan123
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#10

Re: Watt Calculation to Make a Specific LED Light

12/03/2019 4:08 AM

First of all thank you all very much for your time and knowledge. I read all the comments and links provided.

My target was to make Bili light or LED light for the phototherapy to cure newborns jaundice in a cheap rate so that people who are suffering in the villages in Bangladesh can afford. I had a intention to give them free.

Specifications I provided is the UK and who standard. More specifically

  1. Surface area 2 ft x 1 ft
  2. Hight fm Surface >_2 ft
  3. Upto 12° beam angle 470+/- 10 nm
  4. 12° - 30° 440~480 nm
  5. Rest 440 ~ 490 nm
  6. irradiance of at least 30 μW / cm² / nm but not over 60 μW / cm² / nm
  7. Temp 30°~ 40° C

Just tell me how to make local Light shopkeeper to understand to build this LED how much should be the power (watt) . rest structure I'll design.

More cheaper more easier for me to give it to thise people.

If you need more info let me know.
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SolarEagle
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#11
In reply to #10

Re: Watt Calculation to Make a Specific LED Light

12/03/2019 4:35 AM

https://www.ledsupply.com/led-kits

https://www.theneolight.com/

Buy one and adapt it to your own specifications

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Just an Engineer
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#12

Re: Watt Calculation to Make a Specific LED Light

12/04/2019 6:09 AM

Hello and thanks for your good intentions.

Getting the LED to light within the nominated parameters would be directly available from the supplier, with probable 5V DC, 12 V DC and some other options.

To find your energy intensity in the target area (remember to compensate for the "thickness" of the child) I would suggest that you contact a local photographer who will have a "near enough" light meter and then adjust the spacing and height to achieve your intended outcome.

The manufacturing tolerances for LEDs and the other components of your proposed arrangement will thus be reduced to the single error in the reading instrument.

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TahmidKhan123
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#13
In reply to #12

Re: Watt Calculation to Make a Specific LED Light

12/04/2019 9:29 AM

Thanks a lot.
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SolarEagle
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#14
In reply to #12

Re: Watt Calculation to Make a Specific LED Light

12/07/2019 4:10 AM

$15 at the Walmart...

Free phone apps

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TahmidKhan123
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#15
In reply to #14

Re: Watt Calculation to Make a Specific LED Light

12/07/2019 7:15 AM

Thanks a lot
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Just an Engineer
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#16
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Re: Watt Calculation to Make a Specific LED Light

12/08/2019 4:30 AM

Hello and thanks also to you.

As a new person here, you have noted the responses to your question and responded.

Welcome to CR4.

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Users who posted comments:

Just an Engineer (2); lyn (1); Mikerho (1); PWSlack (2); redfred (1); SolarEagle (4); Stef (1); TahmidKhan123 (4)

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