LED bulb changes brightness


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Old 09-11-19, 04:55 AM
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LED bulb changes brightness

I have a 16w Sylvania LED bulb in an enclosed fixture (glass globe) hanging over a table.

It's been fine for years but now its brightness randomly changes. I've looked up causes, but the topics I've come across have mainly been to describe an LED "flickering." I wouldn't use that term for what's going on here: the brightness is consistent for a long while, then suddenly gets dimmer, stays that way for a while (I haven't noticed a particular amount of time) then brightens again. I think of "flickering" as describing something relatively rapid.

There is no dimmer switch on the circuit. I'm not aware of any device on the same line that might be pulling a lot of current. When the bulb dims I've unscrewed it and checked the voltage: 120v, though it's possible that it's simply normalized by the time I got the leads on.

Is this just a matter of the bulb reaching end of life? It's been there a few years.
 
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Old 09-11-19, 05:32 AM
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Some LED bulbs are dimmable. How they do it is by reading the voltage coming into the bulb as a brightness command. A change in your house's voltage could be interpreted as a dimming command by the bulb.

Or, the bulb can be nearing the end of it's life. The internal electronics could be starting to waver and can no longer supply a consistent voltage to the LED emitters.
 
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Old 09-11-19, 05:57 AM
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I'd say it's the end of life. Just read a very detailed article about bulbs. Can't recall the article or the author. But the long and short, all bulbs, be it LED, filament. CFL, will degrade and change in brightness and color as time goes on. Much of it will be due to quality control (by design or otherwise).

This may be common knowledge to some or news to others, but in the early and mid 20th century there was a consortium of all light bulb manufactures to actually control the life span of bulbs. They all agreed on specific specifications in order to increase the sales of light bulbs. I'm certain the same is happening now with LED's but its much more hidden from the government regulatory agencies.
 
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Old 09-11-19, 05:16 PM
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I have a 16w Sylvania LED bulb in an enclosed fixture (glass globe) hanging over a table.
Yup...... time to replace it. LED bulbs can run very hot in confined globes.
 
 

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