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Author Topic: Just one quick bitch, part two  (Read 217425 times)

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Offline odeon

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Re: Just one quick bitch, part two
« Reply #13665 on: October 29, 2017, 04:25:12 PM »
While unlikely, it is certainly possible for a LED to fail quickly. The 20,000 hour figure is an average; we're talking about semiconductors and it is perfectly normal for a small percentage of them to fail quickly.
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Offline 'andersom'

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Re: Just one quick bitch, part two
« Reply #13666 on: October 29, 2017, 04:27:03 PM »
Averages can be a bitch.
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Re: Just one quick bitch, part two
« Reply #13667 on: October 29, 2017, 04:41:10 PM »
That's a quick death for a LED light. My first is from before 2009 and it's still working. Main light in the living room, so gets use quite a lot.

I have had mixed luck with them the shorted was a 100 watt equivalent in the kitchen that didn't even last three months the best is a 40 watt equivalent in the hallway that has been there since 2013 and has only been off when we have lost power
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Offline Queen Victoria

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Re: Just one quick bitch, part two
« Reply #13668 on: October 29, 2017, 05:34:20 PM »
If you can find them light bulbs made for traffic lights have a loooooooooooooooooooooooooooooooooong life.  How often do you see them replacing them?
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Re: Just one quick bitch, part two
« Reply #13669 on: October 29, 2017, 09:26:42 PM »
If you can find them light bulbs made for traffic lights have a loooooooooooooooooooooooooooooooooong life.  How often do you see them replacing them?


I have a few of those(in the two traffic lights I have) though around here they have switched over t leds on most traffic lights
"Eat it up.  Wear it out.  Make it do or do without." 

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Re: Just one quick bitch, part two
« Reply #13670 on: October 29, 2017, 09:30:08 PM »
While unlikely, it is certainly possible for a LED to fail quickly. The 20,000 hour figure is an average; we're talking about semiconductors and it is perfectly normal for a small percentage of them to fail quickly.

From the ones I have had fail and dissected it seems to be the power supply that goes 
"Eat it up.  Wear it out.  Make it do or do without." 

'People who say it cannot be done should not interrupt those who are doing it.'
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Offline Lestat

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Re: Just one quick bitch, part two
« Reply #13671 on: October 29, 2017, 10:29:39 PM »
LEDs are quite unlike many other types of bulb, in that with most, a substantial energy discharge is required, and they get quite hot during use, such as the familiar incandescent bulbs that light our homes, high pressure sodium vapor lamps in the streets, xenon and mercury arc lamps and others, whilst LEDs need to run cold as possible ideally to avoid breakdown of the semiconductor junction. So it stands to reason that the more electrical power consumed (I.e the greater the wattage of the LED) the shorter the lifespan will be.
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Re: Just one quick bitch, part two
« Reply #13672 on: October 30, 2017, 12:59:43 AM »
If you can find them light bulbs made for traffic lights have a loooooooooooooooooooooooooooooooooong life.  How often do you see them replacing them?
I have a few of those(in the two traffic lights I have) though around here they have switched over t leds on most traffic lights
Ooooh. Do you have a picture of those traffic lights? They were a great interest of mine as a kid.
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Re: Just one quick bitch, part two
« Reply #13673 on: October 30, 2017, 01:40:16 AM »
Another site I use seems to have suffered some sort of database snafu, a fair bit of stuff has been lost and damned if part of it wasn't a PM that contained some very important info. Bollocks.
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Offline Charlotte Quin

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Re: Just one quick bitch, part two
« Reply #13674 on: October 30, 2017, 04:49:24 AM »
Painful right shoulder. It seems to be a daily constant lately.

Offline Lestat

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Re: Just one quick bitch, part two
« Reply #13675 on: October 30, 2017, 06:31:00 AM »
Any idea how you might have done it? hope it recovers soon. *brings re-usable NaOAc-type hotpacks, and waits around in a spare room for a day or two doing a few things involving keeping the windows very well open, and carefully scrubbing the stench of butyric acid before it can get into your room in order to provide some pain relief that isn't near enough useless OTC shite*
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Re: Just one quick bitch, part two
« Reply #13676 on: October 30, 2017, 07:01:37 AM »
I dunno really, maybe a bad combination of sleeping on it funny, always using my right hand/arm for carrying things and bad posture.
Feels like joint pain or some sort of torn muscle.

I found some precious precious codeine tabs in my desk drawer the other day but I'm saving it for a rainy day.

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Re: Just one quick bitch, part two
« Reply #13677 on: October 30, 2017, 11:16:19 AM »
Sorry renaden I don't have pictures.  I see that some others have posted some.
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Offline odeon

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Re: Just one quick bitch, part two
« Reply #13678 on: October 30, 2017, 01:05:37 PM »
While unlikely, it is certainly possible for a LED to fail quickly. The 20,000 hour figure is an average; we're talking about semiconductors and it is perfectly normal for a small percentage of them to fail quickly.

From the ones I have had fail and dissected it seems to be the power supply that goes

Makes sense.
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Offline Lestat

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Re: Just one quick bitch, part two
« Reply #13679 on: October 30, 2017, 03:18:47 PM »
I'd imagine that putting them under a reverse bias of any significant level in excess of the power rating would do a pretty decent job of buggering the N/P junction in the diode too. Conventional diodes (that is, purely electrical, and of the semiconductor diode type, obviously there is no P/N junction to destroy in a vacuum tube diode, although these are not common nowadays, most being semiconductor diodes, the LEDs are, as are both conventional electrical diodes and those users for laser applications, which are often based on gallium arsenide, a compound of the elements gallium and arsenic) can only handle so much, which is obvious from the fact that different ratings are available for different applications. (essentially a regular diode being operated, wrongly, as if it were an avalanche diode, and the resulting reverse-biased avalanche breakdown permanently wrecks it)

Diodes are, essentially an electronic one-way valve, designed to allow current to pass in one direction and arrest it in the other. Used for such applications as for arresting back EMF such as when sending an electric pulse through a pair of electrodes connected by a conductor which is in contact with (or in some applications , like plasma railguns for example, partially vaporized by the current dumped into it forming a conductive plasma, the plasma acting both as a conductor, and being ionized gas, plasma pressure itself, forming behind the projectile, serving to push forward the round in a plasma railgun) and which then moves out from between the electrodes, if the current is thus interrupted, a back-flowing EMF spike ends up headed towards the power supply which can make a mess of things, especially in the case of say, something like a high-energy, powerful marx generator being used as a pulsed power supply and electrolytic capacitors being used, as electrolytics are polarized and subjecting them to reverse bias damages the dielectric (and needless to say, you go and blast many farads worth of stored energy at hundreds of kilovolts or more through the railgun, the resulting backwash, if allowed to reach the power supply and not be arrested before it gets to the cap bank the Marx generator is made with is going to worse than just damage the dielectric. Never done so but I should think it would blast the caps to pieces)

Which again, quite obviously is not what you want your face anywhere near when your eye is up against sight, taking aim :autism:
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