Terminology: Difference between revisions
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;<span id="OTF">OTF</span>: Out-the-front. The amount of light that is actually emitted out of the front of the light, usually measured in lumens. This number is always lower than lumens measured at the emitter (at the LED itself). Some manufacturers quote OTF lumens and others use emitter lumens. Usually the OTF value is around a third less than the rated output of the light-producing device. See [[Light Output Measurements]]. | ;<span id="OTF">OTF</span>: Out-the-front. The amount of light that is actually emitted out of the front of the light, usually measured in lumens. This number is always lower than lumens measured at the emitter (at the LED itself). Some manufacturers quote OTF lumens and others use emitter lumens. Usually the OTF value is around a third less than the rated output of the light-producing device. See [[Light Output Measurements]]. | ||
;P60 drop-in: an assembly of the reflector, bulb, and driver originally introduced by [[SureFire]], but now an industry standard. See article [[ | ;P60 drop-in: an assembly of the reflector, bulb, and driver originally introduced by [[SureFire]], but now an industry standard. See article [[P60]] | ||
;pill: a housing for the driver and a mounting point for the LED. In smaller lights it is threaded on the outside and screws into the throat of the flashlight body. | ;pill: a housing for the driver and a mounting point for the LED. In smaller lights it is threaded on the outside and screws into the throat of the flashlight body. | ||
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;preflash: when a light is turned on and emits a short burst of brighter light before settling down to the correct output level | ;preflash: when a light is turned on and emits a short burst of brighter light before settling down to the correct output level | ||
;protected: Preventing damaging [[Rechargeable#Lithium_Ion_.28Li-ion.29_-_3.7V.2Fcell|Li-Ion]] cells by excessive discharge or current, either by a protection circuit built into the battery, or (in some flashlights) by the light turning off or going to a lower level. | ;<span id="protected">protected</span>: Preventing damaging [[Rechargeable#Lithium_Ion_.28Li-ion.29_-_3.7V.2Fcell|Li-Ion]] cells by excessive discharge or current, either by a protection circuit built into the battery, or (in some flashlights) by the light turning off or going to a lower level. | ||
;<span id="PWM">PWM</span>: Pulse Width Modulation. A technique of varying the brightness of a LED by flashing it on and off very quickly, making it appear to the eye that the LED is dimmer. Good PWM is at such a high rate that you can't notice it. But if you wave your hand in front of the light and get a strobe effect, the PWM is getting too low. Some use current regulation which makes the light dimmer without PWM and is also more efficient. | ;<span id="PWM">PWM</span>: Pulse Width Modulation. A technique of varying the brightness of a LED by flashing it on and off very quickly, making it appear to the eye that the LED is dimmer. Good PWM is at such a high rate that you can't notice it. But if you wave your hand in front of the light and get a strobe effect, the PWM is getting too low. Some use current regulation which makes the light dimmer without PWM and is also more efficient. | ||
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;<span id="UI">UI</span>: user interface. The button presses, head twists, and whatever else is required to operate the flashlight, get to various modes, etc. | ;<span id="UI">UI</span>: user interface. The button presses, head twists, and whatever else is required to operate the flashlight, get to various modes, etc. | ||
;unprotected: see protected. | ;unprotected: see [[#protected|protected]]. | ||
;<span id="Vf">Vf</span>: Forward Voltage (a property of an [[LED]]). The voltage drop across a LED at a given current. | ;<span id="Vf">Vf</span>: Forward Voltage (a property of an [[LED]]). The voltage drop across a LED at a given current. | ||