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Dimmers and LED bulbs - does the dimmer shorten the life of the LED bulb?

Dimmers and LED bulbs - does the dimmer shorten the life of the LED bulb?

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  #1  
Old 02-21-14, 05:09 AM
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Dimmers and LED bulbs - does the dimmer shorten the life of the LED bulb?

I'm changing out incandescent for LED bulbs around the house. some are on dimmers. The package of the LED bulb says they ARE dimmable and the existing dimmers do lower the brightness. But my OCD / compulsiveness makes me wonder if the dimmers are beating up the LEDs? There's different types of dimmers, right? Does it matter what type is used for LEDs?

in 1 room, I have a 15+ years old rotary dimmer (resistive?) and in another room we have a 2 year old tiny slide dimmer built right next to the toggle on / off switch. Either is just as good?

Do LEDs not 'like' to run at lower than full power? I know a dimmer extends the life of incadescents. Is it the same or opposite for LEDs and their electronics? And is it based on the type of dimmer being used?

THANK YOU!
 
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  #2  
Old 02-21-14, 08:47 AM
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It all depends on your bulbs. Some can work with almost any type of dimmer and since yours are working you may be lucky. Don't worry about your old dimmers beating up the LED's though. In general LED's are on or off. Dimming is accomplished by rapidly pulsing them on and off. The more time the LED is on the brighter it is. Circuitry in the bulb senses the change in input voltage from your dimmers and treats that as a dimming signal and adjusts the pulsing of the LED's accordingly.

Will dimming make the LED's last longer? Probably. Since a dimmer LED spends less time "on" then it is working less and should last longer. Unfortunately just like CFL bulbs the bulb contains many, many components so the actual LED emitter is probably the least of your worries. A failure of any component or connection among the components can cause it to fail. The LED and each individual component may have an estimated 10'000 hour life but multiply the estimated failure rate by the number of components and the actual life can often be less than advertised.
 
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Old 02-22-14, 02:44 AM
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I have a 15+ years old rotary dimmer (resistive?) and in another room we have a 2 year old tiny slide dimmer built right next to the toggle on / off switch. Either is just as good?
There are NO resistive dimmers in any house of average size. The elementary school I attended had a pair of resistive dimmers for auditorium lighting and they were approximately 18 inches in diameter with a lever handle that rotated around the circumference.

ALL residential dimmers used in the last forty years have been variations on a SCR (silicon controlled rectifier) circuit. They operate by only conducting electricity for a portion of the AC sine wave. The DO generate some heat but not anywhere near what a resistor-type dimmer would produce.

Prior to SCR dimmers some high-end residences used variable auto-transformers to vary the voltage level. These used a large wall box to contain the unit. Watch reruns of the old TV show Bachelor Father and you can see one next to the front door, it has a large round dial about three inches in diameter centered in a plate that is probably six inches square. The auto-transformer dimmers were/are very efficient but they cost a comparatively huge sum and take up a lot of space so they are rarely used these days.
 
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