RMSK, Inc.        
Page 1 of 5 12345 LastLast
Results 1 to 30 of 123

Thread: Beginner's Guide to explain simple LED flashlight.

  1. #1
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Beginner's Guide to explain simple LED flashlight.





    Here is a "Beginner's Guide" to explain simple LED flashlight concepts.
    To show how it works.

    1. Reflector or Lens - used to control beam pattern, change angle of projection.
    The reflector profile is the most important aspect in if the beam if tightly focussed or spread out to give flood light. Deep reflectors typically create a tight spot and shallower reflectors a flood beam. The reflector surface finish then goes towards smoothing out the beam (using a textured surface) or reducing losses (with a mirror finish) but potentially having artefacts in the beam.
    Flashlight Beam Patterns
    http://www.youtube.com/watch?v=f4L1uIcbalQ#t=43
    Reflector vs. Optics: Light Loss
    http://www.candlepowerforums.com/vb/...ics-Light-Loss


    2. LED - Light-emitting diode, the modern Led is much brighter than Incan bulb and life span is much longer too. The efficiency or brightness of Led will be improved every year.
    for more details, please take a look:
    Commonly Used LED Emitter Index
    http://www.candlepowerforums.com/vb/...-Emitter-Index
    Bin Coding: Color, Flux and Vf Charts and Links for Popular White LEDs
    http://www.candlepowerforums.com/vb/...=color+binning


    3. Heatsink - Cooling is required to remove the waste heat produced by Led. Consequent heating according to workload.
    Brighter = Hotter. Nowaday the metal body of flashlight use as heatsink.
    easy explanation asked for aluminium/Copper/silver, pls
    http://www.candlepowerforums.com/vb/...light=Heatsink
    Heat Management Issues
    http://www.candlepowerforums.com/vb/...rent+regulated

    4. Electronic Driver - control the power and signal to led.
    The driver play a very important role here, because the led need ~3-4V only, but the battery capacity will drop according to life.
    The driver can control the brightness by varing by current (or PWM)
    eg. 1.5V AA battery boost driver (step-up) to ~3V to Led. or 2x Li-ion 8.4V battery buck driver (Step-down) to ~3V to Led.
    eg. 3 diffenent power level - High, middle, low.
    Driver board list / regulator board list
    http://www.candlepowerforums.com/vb/...tor-board-list
    Led amperage basic question
    http://www.candlepowerforums.com/vb/...rent+regulated
    PWM - What is it, How does it work and how to detect it.
    http://www.candlepowerforums.com/vb/...&highlight=pwm
    Constant Current vs. PWM dimming Revealed
    http://www.candlepowerforums.com/vb/...mming-Revealed
    (PWM control) AMC7135 Specs Inside **UPDATE**
    http://www.candlepowerforums.com/vb/...amc7135+driver

    5. Battery - AA, AAA, CR123, Li-ion 18650 .......
    Battery Shoot Out
    http://www.candlepowerforums.com/vb/...ds-of-Interest
    Before jumping to Lithium battery, please see: The dangerous side of batteries
    http://www.candlepowerforums.com/vb/...e-of-batteries

    6. Switch - Control On and OFF, change power level
    Forward Clicky:
    - light comes on before it clicks
    - momentary on (when the light is OFF you can half press the switch to flash the light ON)
    - you cannot use the switch to change mode (in certain multi-mode lights) without completely turning off the light
    Reverse Clicky:
    - light come on after it clicks
    - momentary off (when the light is ON you can half press the switch to momentarily turn the light OFF)
    - you can use the switch to change modes (in certain multi-mode lights) while the light is turned on
    Twisties:
    - Turn the of head or tailcap, like MiniMag


    Useful Link:
    Simple guide to using a DMM for measurements
    http://www.candlepowerforums.com/vb/...r-measurements
    Please remind me if anything can explain things more effectively. Thanks!
    Last edited by download; 07-27-2017 at 08:00 PM.

  2. #2

    Default Re: Beginner's Guide to explain simple LED flashlight.

    i think you have got the basics right, you seem to have a clear understanding as a beginner.
    so what's your question please?


  3. #3

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Good job and this will help people. I like it when it is very simple and easy on the eyes.


    He is just adding it to help others out. Plus allowing others to add stuff to the help section of it.
    Here is a "Beginner's Guide" to explain simple LED flashlight concepts.
    To show how it works.
    Quote Originally Posted by shelm View Post
    i think you have got the basics right, you seem to have a clear understanding as a beginner.
    so what's your question please?


  4. #4
    Flashaholic* subwoofer's Avatar
    Join Date
    May 2010
    Location
    Hove, UK
    Posts
    2,359

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Nice looking diagram.

    A couple of minor things come to mind:


    In the LED section I would not compare an LED to a CPU. If anything the better computer analogy would be to compare the LED to the screen. The LED is the output device not the controlling device.


    Reflectors and if they are smooth or textured are not the only factors affecting the beam. The reflector profile is the most important aspect in if the beam if tightly focussed or spread out to give flood light. Deep reflectors typically create a tight spot and shallower reflectors a flood beam. The reflector surface finish then goes towards smoothing out the beam (using a textured surface) or reducing losses (with a mirror finish) but potentially having artefacts in the beam.

    The Aspheric lens creates a great deal of loss of output as it typically focuses only the directly emitted light and cannot meaningfully include light collected by a reflector. The tight pencil beam is fun and light-sabre like but is of little practical use.

    Just an initial reaction. Nice idea for new CPFers to find.
    Tactical Reviews by Subwoofer
    Latest Reviews - @TacticalReviews and Facebook
    CandlePower Forums "Trusted Product Tester / Reviewer"

  5. #5
    Flashaholic* subwoofer's Avatar
    Join Date
    May 2010
    Location
    Hove, UK
    Posts
    2,359

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Oh, one other thing, the reverse vs forward clicky thread you link to is a bit confused why not simply say:

    Forward Clicky:
    - light comes on before it clicks
    - momentary on (when the light is OFF you can half press the switch to flash the light ON)
    - you cannot use the switch to change mode (in certain multi-mode lights) without completely turning off the light
    Reverse Clicky:
    - light come on after it clicks
    - momentary off (when the light is ON you can half press the switch to momentarily turn the light OFF)
    - you can use the switch to change modes (in certain multi-mode lights) while the light is turned on
    Tactical Reviews by Subwoofer
    Latest Reviews - @TacticalReviews and Facebook
    CandlePower Forums "Trusted Product Tester / Reviewer"

  6. #6
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    When I first saw the Led flashlight, I wanted to find how it works, but no a single post to show in simple way.
    That is the reason I want to make it for a long time. Especially here CPF have millions useful posts can tell the story.

    Quote Originally Posted by shelm View Post
    i think you have got the basics right, you seem to have a clear understanding as a beginner.
    so what's your question please?


  7. #7
    Flashaholic*
    Join Date
    Apr 2008
    Location
    Cleveland,Oh
    Posts
    2,379

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Quote Originally Posted by download View Post
    When I first saw the Led flashlight, I wanted to find how it works, but no a single post to show in simple way.
    That is the reason I want to make it for a long time. Especially here CPF have millions useful posts can tell the story.

    I think Shelm missed your join date, post count, and doesn't know your M@g modding history.

    Nice job, you show the basics very clearly. I do understand the CPU comment, both gain efficiency at about the same rate over time.
    Great spirits have always encountered violent opposition from mediocre minds.
    -- Albert Einstein

  8. #8
    Retired Administrator Norm's Avatar
    Join Date
    Jun 2006
    Location
    Australia
    Posts
    9,515

    Default Re: Beginner's Guide to explain simple LED flashlight.

    I've made this a sticky.

    Norm

  9. #9
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    KILLER_K, subwoofer & jabe1,

    Thanks for your input.
    Hope we will make it even better.

  10. #10
    Flashaholic* Obijuan Kenobe's Avatar
    Join Date
    Sep 2010
    Location
    Rotterdam, Netherlands
    Posts
    1,023

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Is it something to illustrate how the body of the light is used as the negative path?

    obi
    Stay sharp and bright for life.
    Have your knife and light handy at all times.
    Sent from a long time ago, in a galaxy far, far away.

  11. #11
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Picture added,

    Quote Originally Posted by Obijuan Kenobe View Post
    Is it something to illustrate how the body of the light is used as the negative path?

    obi

  12. #12
    Flashaholic*
    Join Date
    Apr 2008
    Location
    Cleveland,Oh
    Posts
    2,379

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Under the Electronic Driver designation, note that an LEDs intensity is varied by current (or PWM) and not voltage.
    Great spirits have always encountered violent opposition from mediocre minds.
    -- Albert Einstein

  13. #13

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Nice! Thanks for taking the time to do this!
    ....

  14. #14
    Enlightened T-3's Avatar
    Join Date
    Dec 2009
    Location
    Airdrie, Alberta
    Posts
    42

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Very nice of you to take the time to post this. Helps broaden the understanding of someone like myself who lurks here once in a while!

  15. #15

    Default Re: Beginner's Guide to explain simple LED flashlight.

    This is great for those of us new to this hobby. Great visual aid helps me quickly understand the relationship between all components. Thanks for posting .

  16. #16

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Thanks big help

  17. #17

    Default Re: Beginner's Guide to explain simple LED flashlight.

    That was surely a big help ! I was teaching my kids the other day and got a question about LED flashlights. I searched all over the net didint find anything easy to grasp. Got to your blog and I found the wanted piece of wisdom. Thanks again. Keep sharing .

  18. #18
    Enlightened
    Join Date
    Sep 2013
    Location
    Shenzhen China
    Posts
    22

    Default Re: Beginner's Guide to explain simple LED flashlight.

    I like your diagram, it helps a lot for a rookie like me

  19. #19
    Unenlightened
    Join Date
    Aug 2013
    Posts
    1

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Fantastic. Well done. Easy to understand for us new to the LED flashlight building/modding

    Thank You

  20. #20

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Quote Originally Posted by Norm View Post
    I've made this a sticky.

    Norm
    What is a sticky? Is it a cpf function that allows me to easily bring this page up for reference? Cheers.
    Last edited by Lomandor; 09-23-2013 at 03:41 PM.

  21. #21
    Unenlightened doceric's Avatar
    Join Date
    Sep 2013
    Location
    Manila
    Posts
    6

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Thanks! This is really helpful for beginners like me..

  22. #22
    Unenlightened
    Join Date
    Oct 2013
    Posts
    1

    Default Re: Beginner's Guide to explain simple LED flashlight.

    OK, now understand that I'm a true beginner, with little understanding of technical issues. That said, I have two problems with the following quote from the original post. I'll overlook the first as a mere typo, but the second I truly don't understand:

    "...life spin is much longer too. The brightness of newer Led will increase ~30% per year."

    INCREASE? How long until it's brighter than the sun?

  23. #23
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Thanks for reminding. Is it better like that?

    The efficiency or brightness of Led will be improved ~30% every year.
    Last edited by download; 10-18-2013 at 02:29 AM.

  24. #24

    Default Beginner's Guide to explain simple LED flashlight.

    Nice


    Sent from my iPhone using Tapatalk - now Free

  25. #25
    Unenlightened
    Join Date
    Sep 2013
    Posts
    1

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Great Beginner's Guide
    thanks..

  26. #26

    Default Re: Beginner's Guide to explain simple LED flashlight.

    This might be a stupid question but the heatsink reminded me to ask. Why do our LED flashlights emit so much heat. I thought LEDs were supposed to run cool. In fact the 100 watt bulbs I have installed in my ceiling can light fixtures are completely cool to the touch. Why such a difference between applications.

  27. #27
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Fluorescent lamp and LED (Light-emitting diode) are different technology, just like gasoline engine car and pure electric car.
    The outlook are similar but they use two different kind of technology inside.

    For more technical details, please see:
    http://en.wikipedia.org/wiki/Light-e..._diode#Physics

  28. #28

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Quote Originally Posted by download View Post
    Fluorescent lamp and LED (Light-emitting diode) are different technology, just like gasoline engine car and pure electric car.
    The outlook are similar but they use two different kind of technology inside.

    For more technical details, please see:
    http://en.wikipedia.org/wiki/Light-e..._diode#Physics
    How did fluorescents enter into the discussion?

  29. #29
    Flashaholic* download's Avatar
    Join Date
    Jun 2005
    Location
    Sol 3
    Posts
    1,619

    Default Re: Beginner's Guide to explain simple LED flashlight.

    Sorry enzo thecat, misunderstood your 100 watt bulbs was Fluorescent lamp.

    Heat is side product when the led is driven by more current.
    Lower current = Higher Efficacy, >0.3A will generate more light per current.
    Higher current = Lower Efficacy, <1A will generate less light per current and more heat.

    eg.1 Led Christmas tree lighting, the loading of led is ~0.05A, cool to touch, right?
    eg.2 Cree XML, when the current load is 0.05A, it will be cool to touch too.
    When the current load reach 3A, it will generate a lot of heat, it will kill itself without suitable heatsink.

  30. #30
    Flashaholic* jamie.91's Avatar
    Join Date
    Aug 2008
    Location
    United Kingdom
    Posts
    668

    Default Beginner's Guide to explain simple LED flashlight.

    What a good thread!
    Four surefires and counting, this could be expensive

Page 1 of 5 12345 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •