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
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 every year.
for more details, please take a look:
Commonly Used LED Emitter Index
Bin Coding: Color, Flux and Vf Charts and Links for Popular White LEDs
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
Heat Management Issues
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.
The basics of LED drivers
Driver board list / regulator board list
Led amperage basic question
PWM - What is it, How does it work and how to detect it.
Constant Current vs. PWM dimming Revealed
(PWM control) AMC7135 Specs Inside **UPDATE**
5. Battery - AA, AAA, CR123, Li-ion 18650 .......
Battery Shoot Out
Before jumping to Lithium battery, please see: The dangerous side of batteries
6. Switch - Control On and OFF, change power level
- 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
- 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
- Turn the of head or tailcap, like MiniMag
Simple guide to using a DMM for measurements
Please remind me if anything can explain things more effectively. Thanks!