Beginner's Guide to explain simple LED flashlight.

[Glenn_San]

Thanks for the helpful diagrams and explanation. I'm researching prior to buying a decent LED flashlight to replace the el-cheapo units I have bought in recent years as they have all failed, probably due to "You-get-what-you-pay-for" quality issues.

It would be so nice to have a new flashlight that will last me many years without reliability issues.

 

[1911litup]

Thank you for putting this information out there. Great overview. I am trying to learn more about creating drivers that are programmable. As I know NOTHING, I have a long way to go

 

[TxRobtrx]

This is a great post for total beginners like me who have just bought flashlights in the past and now want to start becoming an informed consumer. Thanks

 

[psycosteve]

Chalk this up to a noob observation but just looking at the diagrams you could not only modify but existing lights but build them given the right materials. Thank you Download

 

[Dkoi]

A really useful thread, a lot of terminology on this forum was passing my by and this will help my grasp. Thank you.

 

[Invasion]

Thanks for all the info really appreciated. Should help me sort things out

 

[Tactical Michael]

Thanks for the great info, starting to really get into flashlights and this primer really helps.

 

[Luke01]

This helps out alot. Thank you. Does the housing material matter?

 

[PFKMan23]

Thanks for this. It's always good to know the basic workings of things.

 

[Evan12]

I really like this post .you explain really well in nice way.

 

[sanjayram]

company should give some important and basic things about the usage and the improvement that are to be made when someone is using the lights of these kinds

 

[colight]

Thnaks for sharing,I used flashlights for one year ,but I don't know it very well.

 

[likevvii]

Thanks for the guide! I bet the senior members of this forum know all of this stuff by heart!

 

[Amy sunshine]

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/showthread.php?151836-Reflector-vs-Optics-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 ~30% every year.
for more details, please take a look:
Commonly Used LED Emitter Index
http://www.candlepowerforums.com/vb/showthread.php?270419-Commonly-Used-LED-Emitter-Index
Bin Coding: Color, Flux and Vf Charts and Links for Popular White LEDs
http://www.candlepowerforums.com/vb...or-Popular-White-LEDs&highlight=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...luminium-Copper-silver-pls&highlight=Heatsink
Heat Management Issues
http://www.candlepowerforums.com/vb...Management-Issues&highlight=current+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/showthread.php?188227-Driver-board-list-regulator-board-list
Led amperage basic question
http://www.candlepowerforums.com/vb...ge-basic-question&highlight=current+regulated
PWM - What is it, How does it work and how to detect it.
http://www.candlepowerforums.com/vb...es-it-work-and-how-to-detect-it&highlight=pwm
Constant Current vs. PWM dimming Revealed
http://www.candlepowerforums.com/vb/showthread.php?70073-Constant-Current-vs-PWM-dimming-Revealed
(PWM control) AMC7135 Specs Inside **UPDATE**
http://www.candlepowerforums.com/vb...cs-Inside-**UPDATE**&highlight=amc7135+driver

5. Battery - AA, AAA, CR123, Li-ion 18650 .......
Battery Shoot Out
http://www.candlepowerforums.com/vb...ronics-Batteries-Included-Threads-of-Interest
Before jumping to Lithium battery, please see: The dangerous side of batteries
http://www.candlepowerforums.com/vb...d-Close-Calls-The-dangerous-side-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...-Simple-guide-to-using-a-DMM-for-measurements
Please remind me if anything can explain things more effectively. Thanks!

thanks for your information. if I don't have read your article, I will don't know a tiny torch with such specific information. in addition, it is common that a torch with replaceable battery, and there is a kind of torch with non movable battery , you can charge it after the battery runs out, and we can them when we are going to camp. do you think so?

 

[Amy sunshine]

thanks for you information...

 

[download]

:welcome:

Amy sunshine.
Thanks for your input, the rechargeable flashlight have extra circuit for recharging the battery.
Just like our cell phone nowadays.

 

[Amy sunshine]

do you have a flashlight? and where do you usually get it? from a real store or an online shop? and how do you judge a flashlight according to what factors. thank you...

 

[download]

Amy sunshine,

Sure I own dozens of flashlights. Got them from a real store and an online shop too.
Too many criteria to judge, like, build quality, material used, reliability, battery used, user interface, price..........

For beginner, Please take a look of the below posts, it is good starting.
http://www.candlepowerforums.com/vb/forumdisplay.php?135-Recommend-Me-a-Light-For

And fill the "Checklist", so we could answer your questions.
http://www.candlepowerforums.com/vb...hlight-Recommendation-Checklist-Updated-MK-II

 

[feifei]

How do they test the life span of the LED?Some is claimed to be 100000 hours,how to measure it?

 

[download]

:welcome: feifei

We have some post discuss like below:
http://www.candlepowerforums.com/vb...n-proven-yet&highlight=has+led+longevity+been