how does a 3-way cfl work? i have one and is very different.

how does a 3-way cfl work? i have one and is very different.

Most of them have internal fixed-type dimming circuitry - they just operate the tube at a lower power settings depending on which socket contact is energized (that is, the first & second clicks on a 3-way lamp switch) and full power when both contacts are energized (3rd click).

Some actually use two tubes of two different wattages....like the circline 3-way types.

thats really cool! i always wondered how they worked.

I always wondered how they worked too. Cool to know. I had some they only lasted about 9 months not what it seed on the package.

Very frequently the dimming (mainly the lowest level) is implemented in very crude way (switching from doubler to bridge rectifier configuration, so lowering the DC voltage for the inverter), so it doesn't maintain correct electrode temperature when dimmed, so they sputter away very quickly...

Quote from: lightman64 on January 19, 2009, 11:55:25 AM

how does a 3-way cfl work? i have one and is very different.

Most of them have internal fixed-type dimming circuitry - they just operate the tube at a lower power settings depending on which socket contact is energized (that is, the first & second clicks on a 3-way lamp switch) and full power when both contacts are energized (3rd click).

Some actually use two tubes of two different wattages....like the circline 3-way types.

I would love to find a circline like you mentioned.  The type with two lamps of different wattages.  I have a HUGE table lamp that originally had a 100, 200, 300 3-way incandescent in it.  I now just have a 22 watt circline in it.  Would love an "old school" (preheat) 3 way.  I have even thought about building one if I cannot find one!

I would be thinking about making one by yourselve:
It would be for FC6T9 and FC8T9, as nothing else then serial choke would not fit (and higher wattages need a HX transformer), or you would have to go electronic
Find a can, that would just fit inside the FC6
Find ballasts for these lamps
Find fired 3-way CFL, cut the bottom part with the socket of the ballast box
Make 2..3 holes into it and bolt it to the ballast can
Put two ballasts (FC6 and FC8 one) there
Put starters socket onto the lid (opposite to the thread socket)