LED slow off

[vjp...@at.biostrategist.dot.dot.com]

Is it normal for LEDs to not turn offimmediately?


- = -
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---{Nothing herein constitutes advice. Everything fully disclaimed.}---

[Andy Burns]

vjp...@at.BioStrategist.dot.dot.com wrote:

> Is it normal for LEDs to not turn offimmediately?

do you mean an actual LED, e.g.
<https://www.petervis.com/electronics/led/led/led-pinout.gif>

in which case no.

Or a mains lamp that uses LED, e.g.
<https://cdn.aws.toolstation.com/images/141020-UK/800/70757.jpg>

in which case, it's quite normal for many types to "fade" away as the
internal power supply runs down after it's switched off.

[Phil Allison]

Andy Burns wrote:

-----------------

** Correct.

And just to rub the point in, the yellow phosphor that turns the blue LED light into white has no persistence - unlike the phosphors use in fluoro tubes and scope CRTs or TV picture tubes.



.... Phil

[vjp...@at.biostrategist.dot.dot.com]

Thanks. I though it was wierd. New bulb. It has like a circle of little
dots of light which take a bit to shut down. In my mind LEDs should be the
fastest to shut down. I am deathly afraid of halogen because of fires and I
keep wondering if I got halogen instead.

[Ralph Mowery]

In article <qota2l$h0t$1...@reader2.panix.com>,
vjp...@at.BioStrategist.dot.dot.com says...

> Thanks. I though it was wierd. New bulb. It has like a circle of little
> dots of light which take a bit to shut down. In my mind LEDs should be the
> fastest to shut down. I am deathly afraid of halogen because of fires and I
> keep wondering if I got halogen instead.
>
>
>
>

Most of the LED bulbs ( the 40, 60,100 watt replacements) are made up
of a ring of LEDs that are about 1/8 to 1/4 of an inch square. The long
4 foot tubes are made up of a string of similar small LEDs. They usually
have capacitors in them that hold a charge that takes a second or two to
fully discharge.

What gets me is the LED tubes that I have. Some come on as soon as the
switch is turned on and some take about 2 seconds to come on.

[tabb...@gmail.com]

On Thursday, 24 October 2019 23:54:17 UTC+1, vjp...@at.biostrategist.dot.dot.com wrote:
> Thanks. I though it was wierd. New bulb. It has like a circle of little
> dots of light which take a bit to shut down. In my mind LEDs should be the
> fastest to shut down. I am deathly afraid of halogen because of fires and I
> keep wondering if I got halogen instead.

LED & hlogen look very different, there's no mistaking them.


NT

[Phil Allison]

vjp...@at.biostrategist.dot.dot.com wrote:

---------------------------------------------

>
> I am deathly afraid of halogen because of fires and I
> keep wondering if I got halogen instead.
>

** Well, that is a new phobia to me.

Wot is the fire issue with halogen light bulbs?

None the industry knows of.


..... Phil

[Bob Engelhardt]

It's the "ceiling heater" lamps that have/had the issue. The floor
lamps with 200 or 300w bulbs in upward-facing dish reflectors. The fire
hazard was from curtains getting blown on top of the lamps & catching fire.

[tabb...@gmail.com]

I thought this was fairly well known.


NT

[Tim R]

On Thursday, October 24, 2019 at 7:48:45 PM UTC-4, Ralph Mowery wrote:

> What gets me is the LED tubes that I have. Some come on as soon as the
> switch is turned on and some take about 2 seconds to come on.

Mine do that too. The delay is perceptible and different from the tube fluorescent in the same room.