LED and 3 way light lamps and just some comments.
#1
LED and 3 way light lamps and just some comments.
Recently a customer wanted to know if a LED light could be used in a 3 way switched lamp (not a three way light circuit).
Normally an incandescent bulb could be used at the high level only with no ill affects. However, as I was unsure I told him no it could not be used, but that a specifically designed 3 way LED must be used and even then the lamp circuitry may play a roll in the successful operation of the light.
That night I did some digging on Google and it seems that the use of an ordinary LED bulb may or may not be used in a 3 way lamp. Many factors seem to play a roll including manufacturer, and lamp circuitry. One brave soul tried it with several bulbs and had them explode upon applying power. Others said they had no problem, while still others claimed some success with humming and/or low level brightness.
So the short answer is a definite NO! But you may try at your own risk!
In case anybody should ask.
Normally an incandescent bulb could be used at the high level only with no ill affects. However, as I was unsure I told him no it could not be used, but that a specifically designed 3 way LED must be used and even then the lamp circuitry may play a roll in the successful operation of the light.
That night I did some digging on Google and it seems that the use of an ordinary LED bulb may or may not be used in a 3 way lamp. Many factors seem to play a roll including manufacturer, and lamp circuitry. One brave soul tried it with several bulbs and had them explode upon applying power. Others said they had no problem, while still others claimed some success with humming and/or low level brightness.
So the short answer is a definite NO! But you may try at your own risk!

In case anybody should ask.

#2
That is not only true with LED bulbs but standard bulbs too.
It all depends on how the contacts are set up on the bulb.... and to some extent... the socket too.
It all depends on how the contacts are set up on the bulb.... and to some extent... the socket too.
#3
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Every three level incandescent bulb I have ever seen had the shell contact, the center contact and a ring contact around the center contact. Every three level socket was constructed the same way. Whenever I would use a standard bulb in a three level lamp it would simply turn on and off with every motion of the switch. Even if an LED bulb had a much larger center button contact it should simply turn on with the first click (center contact), continue on with the second click of the switch (ring contact) and still be lit with the third click of the switch (center and ring contacts together) and finally turning off with the fourth click. More likely it would simply turn on and off with each click as would a standard incandescent.
However, if you are referring to a "touch sensitive" switch, where you tap any metal part of the lamp to switch between levels then you are correct, it won't work and it may destroy the LED. Touch sensitive lamps use standard (single light level) bulbs and an SCR circuit to pulse less voltage to the bulb for dimming. This would also be true of any lamp that has a dimmer assembly mounted in the cord or lamp that requires a rotary or sliding motion.
However, if you are referring to a "touch sensitive" switch, where you tap any metal part of the lamp to switch between levels then you are correct, it won't work and it may destroy the LED. Touch sensitive lamps use standard (single light level) bulbs and an SCR circuit to pulse less voltage to the bulb for dimming. This would also be true of any lamp that has a dimmer assembly mounted in the cord or lamp that requires a rotary or sliding motion.