New member here with questions

[StayInTheLight]

Hi this is my first post /ubbthreads/images/graemlins/smile.gif

I have some questions I hope someone here may be able to help me with.

1. How is the brightness of an LED messured?
2. What would be considered enough brightness from a white LED to see your way around in the dark?
3. What color LED consumes the most electricity? What color consumes the next most and so on?
4. What types of LEDs consume the least amount of electricity but still give off enough light to see your way around in the dark?

Thanks for any help in advance. /ubbthreads/images/graemlins/smile.gif

 

[Size15's]

Welcome to CPF!

I'm moving your thread to the LED forum where you should get more answers.

I hope you enjoy your time here.

Best regards,

Al

 

[Charles Bradshaw]

A white LED draws 30 milliamps if driven near specification. This is a standard 5 millimeter Nichia LED. A Luxeon Star draws over 10 times that.

An LED need not be anywhere near as bright as a traditional incandescant bulb to be useful in flashlight applications.

The primary advantages of LEDS over incandescant bulbs are:

No filament to burn out or globe to break.
White light as opposed to yellowish.
Far more efficient with batteries (uses batteries far beyond the point that incan lights die).

I am quite sure that many here will reply with far more pertinent information than I can.

I suggest you get either an Arc AAA (1 AAA) or CMG Infinity Ultra (1 AA). They are about the same brightness.

5 mm LEDs are measured in MilliCandelas (MCD).

 

[TheBeam]

Get both.

 

[IlluminatingBikr]

Welcome to CPF! /ubbthreads/images/graemlins/wink2.gif

I will give my best shot answering your questions.

1. Brightness is commonly measured in lux or lumens. Lux is a measure of brightness in the brightest spot of the beam. Lumen is a measure of total light output.

2. If you drive a 5mm LED at specs (about 3.6 volts and 20 mA) that should be enough to get by in the dark. Examples of single 5mm LED lights are the Arc AAA and the CMG Infinity Ultra.

3. I'm not sure as to the answer of this question.

4. I believe the color your looking for here is red. Red is a very efficent color and should be bright enough for seeing your way around in the dark. Red is also the only color that preserves your night vision. A definite plus!

 

[Doug Owen]

Howdy,

Interesting questions, all. FWIW, light is typically measured by a silicon detector where a photons of light are converted to miliampers of current. I'm not sure if you wanted to know that, but that's the question asked. Another poster has pointed out the difference between Lux (a peak reading with a 'light meter') an Lumens (a total measure requiring an expensive and uncommon sphere). As often as not, subjective measures are used.

Energy used depends on color and efficiency. In general, longer wavelengths (like red) have lower energy per photon so need less energy. Infrared, being even longer wavelength uses even less electricity per unit of light. Efficiency also favors the low end rather than say blue (the base for white LEDs). Overall this means that while you might get 100 Lumens per Watt in Red or Red-orange, you're equally lucky to see 20 in Blue.

All that said, color vision aside, you can see yellow or yellow-green light best of all. As to the question of a what color provides the minimum necessary illumination at lowest energy input, I leave that as an exercise for the students.......

Doug Owen

 

[Double_A]

Howdy-

In my opinion the most useful LED color in terms of brightness, and operates on the lowest forward voltage Vf, and most closely matches the peak sensitivity of the human and which doesn't seem to attract bugs...is the yellow LED.


GregR

 

[Drjones]

Are you looking for a flashlight, or looking to make something yourself?

As others have already done, I too recommend the CMG Ultra and/or the Arc AAA. I have a CMG which runs off of one AA battery, and it is amazingly bright for a single LED.

The Inova X5T is a really cool light that uses five LED's to produce a pretty bright beam of light.

Then you have something like the Surefire L4 which uses a 5 Watt LED that is amazingly bright, based on what I've read here. There are upcoming LED lights from Surefire that will hopefully be even brighter than that! /ubbthreads/images/graemlins/naughty.gif