Emitting Light When Switched Off

Seasons greetings,
I don't know if this is a common thing or not, and it happens to my TM16GT Nitecore, but I guess it could be just as easily any flashlight for that matter. When it is switched off, from any level, the emitters ( x4 in this case ) continue to emit dull and reducing light to nothing, over about 30 seconds or so. Does anyone else experience this phenomena, and is it a common thing? What causes it? It doesn't affect the operation of this extremely reliable flashlight in any other way, and I am just curious to know the reason behind it. Its not even something I would do anything about, if I could. I am just interested to know why it happens.
Thanks in advance.

As an answer to the "why"...basically the circuit that powers the light normally has components (capacitors) which store an electrical charge and because of the way it is designed, once power is removed from the circuit (turned off) those components discharge the power that they had stored up during operation back into the LED. Because of the LED's low threshold voltage requirement, it tends to illuminate when this happens. The reason you don't see this when using a low battery is because the driver circuit has a higher voltage requirement than LEDs themselves, for several reasons but usually to prevent the excessive discharge of Li-Ion cells.

I'm not sure how common it is to find driver circuits that allow this, however it is normal for LEDs to light when given small amounts of power.

There was another thread on the topic when the TM16 or TM16GT first came out - I can not remember which. I know mine did this very slightly. I just put it down to residual emissions from the LED phosphors as they returned to their neutral state.

Thanks guys.

:twothumbs

My Malkoff M61N does that.
When I noticed it I just chalked it up to phosphor afterglow, just like those on fluorescent lights.

I've experienced this on many flashlights and its nothing to worry about. I noticed that it is especially common with anything high powered (i.e. 5000 lumen+). I did a lot of experimentation and found that even if I unscrew the battery tube the LED's continue to glow. I also put it down to phosphor afterglow in the end. Though perhaps it could be the circuit too. Who knows...:thinking: