Trinity, Ishtim, PsYkHoTiK or any fluorescent light expert, I need your help!

Discussion in 'Lounge' started by zy, Apr 11, 2011.

  1. zy

    zy Staff Member

    Ok, so my friends house has some fluorescent light (tube style) in the kitchen.

    I only know it has 2 tubes and is controlled by a dimmer switch.
    The problem is that, the light output is dim and flashing/flickering.

    I know how a normal fluorescent circuit works, but I am not familiar with the ones that have a dimmer switch attached.

    What could be wrong here?
    • Ballast? (Does it have one)?
    • Tube? (I don't think both will go out at the same time right? Or maybe I should ask my friends if both went out together or one by one)
    • Dimmer switch?
    • Something else?
  2. Chai

    Chai Administrator Staff Member

    Does it work normally at full power?
  3. Trinity

    Trinity Little Kiki Staff Member

    AFAIK, Dimmers don't work very well at all with fluoresent lights.

    My first guess would be the bulbs need replaced.
  4. PsYkHoTiK

    PsYkHoTiK Admin nerd

    Yeah that's my thoughts too.
  5. zy

    zy Staff Member

    I don't know :confused:

    Yeah, dimmers. I wonder how old is the dimmer.

    Maybe I'll buy 1 tube and test? :lol:
    I only know it has 2 tubes. I wonder will it run with just 1 tube alone :confused:
  6. Trinity

    Trinity Little Kiki Staff Member

    If I had my way I'd ban fluoresent lights and keep strong the incandescent light bulbs!:dance:
  7. DarKSeeD

    DarKSeeD BOG Translator

  8. Chai

    Chai Administrator Staff Member

    LOL, I'm quite a fan of fluorescent lights as they are much cooler.
  9. empire23

    empire23 BRB. Attacking Russia

    They aren't compatible without the correct circuitry in the balast stage.

    Very simply, fluorescent lights operate off the principle that an arc discharge causes electrons to jump, the jumping electrons react with the gas or vapour to create UV light, the UV light then gets converted to visible light as it strikes the interior coat. Now you have the basics!

    Most dimmers operate off the principle of PWM or known as Pulse Width Modulation, that means a switch is opened for 50 percent of the cycle time, which in theory would mean an energy delivery of 50 percent the total demand, usually done with a cool thinggy called a transistor. Thinking of it as flicking a light switch really really really fast.

    Fluorescent lights have balasts, which are generally inductors, that resist a change in current. When you switch the current off quickly (as by using a dimmer), the inductor resists the loss of current, but in the process, dropping voltage. Because the lamp requires a certain voltage to create an arc to produce electrons, the voltage drop is not taken too kindly by the cathode.

    So when the dimmer starts power back to the lamp during the on phase of its duty cycle, it has to reheat the cathode, which during the off phase has cooled down below the temperature in which it emmits electrons, thus the flickering.

    TL;DR = Tough shit, those lamps aren't meant to work with dimmers unless they have some sort of capacitor put in to resist a change in voltage (which in itself can cause an issue during start up)
  10. zy

    zy Staff Member

    No idea. Don't me why my friends kitchen have a dimmer for fluorescent lamp.

    I checked online, and the parts for dimmable fluorescent lamp tube (dimmer & ballast) are freaking expensive.

    There's even dimmable CFL :lol: which is suppose to work with traditional dimmers :lol:

    Well, I asked my friend to contact the landlord regarding the fluorescent lamp. :p
  11. Ishtim

    Ishtim Super Moderator

    Well said...

    Bottom line is that most flourescent setups are NOT intended for dimmer switches. :silenced:
  12. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Yeah, one of the "problems" with flourescent lights or CFL is that they are mostly not compatible with dimmers. Sure, they have dimmer-compatible ones but they are expensive and very rare. In fact, I don't know of any here in Malaysia.

    I used to have dimmers in my condo, but I had to use incandescent light bulbs with them. It won't work if I screw in a CFL.

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