The most important part of flashlight is the light source, and today 5mm LEDs are largely used. In addition to the LED, light distribution also determined by the reflector and how far a torch lit.
A wide range of bright emitting can be reached only through adequate focusing of the bright, for that reason, you need a large, deep reflector. Usually reflectors have slightly textured surface to scatter light and thus to achieve uniform light beam. This orange peel-like structure is called OP, and smooth reflectors with high-gloss surface is called SMO.
They not only provide high energy density, but also in practice has 3.7 volts for LEDs voltage range. Lithium-ion battery (cells) are available in many different sizes. The different numbers seem to be very confusing at first glance, but easy to understand: the first two digits are the diameter, the next two are the length in millimeters and the last digit describes the cylindrical shape. Such as, the 18650 cell has a diameter if 18mm and is 6.5 inches (65mm) long. The following table provides an overview of the different cell sizes and the possible combinations. Thus, for example, two 17500 cells can replace the three CR123A batteries (16340) in a Surefire G3 / M3 / C3.
The actual sizes may vary sightly, cells with protected electronics are higher than the same model in unprotected, typically 1-2mm.
Reflector
The reflector determines the light distribution between the bright hotspot in the center and the rest of the glow. For the purpose, the light has Throw (how far the lamp throws light) and Spill (for the scattered light) classified. Most lights are mixture of both under workable optimum, so we can view enough spill to the straight ground and a bright hotspot for longer distance.
a smooth SMO reflector in comparison with the
structured surface of a OP reflector
A wide range of bright emitting can be reached only through adequate focusing of the bright, for that reason, you need a large, deep reflector. Usually reflectors have slightly textured surface to scatter light and thus to achieve uniform light beam. This orange peel-like structure is called OP, and smooth reflectors with high-gloss surface is called SMO.
Battery & Charge
Although traditional alkaline batteries or nickel-metal hydride batteries are still possible to operate mant flashlights, lithium-ion batteries have become the most popular power source.
Lithium-ion batteries in comparision
They not only provide high energy density, but also in practice has 3.7 volts for LEDs voltage range. Lithium-ion battery (cells) are available in many different sizes. The different numbers seem to be very confusing at first glance, but easy to understand: the first two digits are the diameter, the next two are the length in millimeters and the last digit describes the cylindrical shape. Such as, the 18650 cell has a diameter if 18mm and is 6.5 inches (65mm) long. The following table provides an overview of the different cell sizes and the possible combinations. Thus, for example, two 17500 cells can replace the three CR123A batteries (16340) in a Surefire G3 / M3 / C3.
| Model | corresponds to the size (Note: the voltage of a charged Li-ion cell is 4.2V!) |
| 10440 | AAA / Micro |
| 14500 | AA / Mignon |
| 16340 | CR123a |
| 17500 | 2x17500 = 3xCR123a |
| 17670 | 2xCR123a |
| 18650 | about as high as 2xCR123a but wider, so for pure CR123a lamps not suitable |
Lithium batteries can only with a special charger
to be loaded (in the picture: UltraFire WF-139 Charger)
to be loaded (in the picture: UltraFire WF-139 Charger)
Protected and Unprotected Li-Ion Batteries
Lithium batteries are offered in a "unprotected" and "protected" version. The difference between these batteries is that a protected cell electronics at the bottom of the battery to protect battery from overcharging or deep discharge. Depending on the application, the advantages and disadvantages may have, novices are protected with the batteries on the safe side. Li-ion batteries are the ideal complement for high-intensity LED lamps. Especially lamps with a 18650 battery provide in practice a perfect compromise between high performance, long life and compact size. Besides, it is not only much cheaper to users in the maintenance rechargeable battery instead of expensive CR123A batteries, but you also have more control over the duration of the flashlight since you can leave away your house with the battery charged.Switch
no difference between the various. outside of switch types are recognizable
Momentary / Tactical switch: The simplest form of switch will control light as long as the switch is pushed down. This is the classic switch from Surefire.
Reverse Clickie: Push the switch down and then release, the light is on; and then a slight pressure to interrupt the control to switch to the next mode. This is the most built-up form of switch, but does not offer the possibility as the Momentary Switch which allows only short flashes.
Inside of a Clickie switch
Forward Clickie: Only when the switch is pressed all way to make it click and the lamp is permanently on. These switches combined with Momentary On click switch makes flashlights without multi-mode in Surefire style.
