Computers and fluorescent lights

Discussion in 'Computer Support' started by rfdjr1@optonline.net, Sep 16, 2006.

  1. Guest

    I just put together a new computer desk with a hutch. I was thinking of getting
    a fluorescent light to put up inder the hutch so at night I don't have to have
    the big ceiling light on. Then I started to wonder if a fluorescent light would
    be a problem near the computer or monitor. I'm thinking of either the flicker of
    the light being a problem looking at the monitor itself or the ballast being a
    problem near the computer tower. Thanks.
    , Sep 16, 2006
    #1
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  2. Guest

    On Sat, 16 Sep 2006 18:59:16 -0400, wrote:

    >I just put together a new computer desk with a hutch. I was thinking of getting
    >a fluorescent light to put up inder the hutch so at night I don't have to have
    >the big ceiling light on. Then I started to wonder if a fluorescent light would
    >be a problem near the computer or monitor. I'm thinking of either the flicker of
    >the light being a problem looking at the monitor itself or the ballast being a
    >problem near the computer tower. Thanks.


    The light tube is harmless, the power supply in the computer puts out more
    electric noise, but the ballest could affect a CRT type of monitor...

    I use a small halogen lamp, 20 watts.
    , Sep 17, 2006
    #2
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  3. wrote:
    > I just put together a new computer desk with a hutch. I was thinking of getting
    > a fluorescent light to put up inder the hutch so at night I don't have to have
    > the big ceiling light on. Then I started to wonder if a fluorescent light would
    > be a problem near the computer or monitor. I'm thinking of either the flicker of
    > the light being a problem looking at the monitor itself or the ballast being a
    > problem near the computer tower. Thanks.


    Office workers have suffered because of the fluorescent lights in their
    respective offices.
    Wikipedia does a good job explaining why as follows:

    "Fluorescent lamps which operate directly from mains frequency AC will
    flicker at twice the mains frequency, since the power being delivered
    to the lamp drops to zero twice per cycle. This means the light
    flickers at 120 times per second (Hz) in countries which use
    60-cycle-per-second (60 Hz) AC, and 100 times per second in those which
    use 50 Hz. This same principle can also cause hum from fluorescent
    lamps, actually from its ballast. Both the annoying hum and flicker are
    eliminated in lamps which use a high-frequency electronic ballast, such
    as the increasingly popular compact fluorescent bulb.

    Although most people cannot directly see 120 Hz flicker, some
    people[1][2] report that 120 Hz flicker causes eyestrain and headache.
    Dr. J. Veitch has found that people have better reading performance
    using high-frequency (20-60 kHz) electronic ballasts than magnetic
    ballasts (120 Hz).[3]

    In some circumstances, fluorescent lamps operated at mains frequency
    can also produce flicker at the mains frequency (50 or 60 Hz) itself,
    which is noticeable by more people. This can happen in the last few
    hours of tube life when the cathode emission coating at one end is
    almost run out, and that cathode starts having difficulty emitting
    enough electrons into the gas fill, resulting in slight rectification
    and hence uneven light output in positive and negative going mains
    cycles. Mains frequency flicker can also sometimes be emitted from the
    very ends of the tubes, as a result of each tube electrode alternately
    operating as an anode and cathode each half mains cycle, and producing
    slightly different light output pattern in anode or cathode mode. (This
    was a more serious issue with tubes over 40 years ago, and many
    fittings of that era shielded the tube ends from view as a result.)
    Flicker at mains frequency is more noticeable in the peripheral vision
    than it is in the centre of gaze."

    If the fluorescent lights alone cuase eye strain and give workers
    headaches, imagine staring at a CRT monitor that is flickering at a
    frequency close enough to the bulb's frequency (60Hz - 50 Hz) to create
    a "wave effect?" It becomes nauseating after a while.

    Fortunately, those users who have fluorescent lighting and CRT monitors
    can adjust the CRT's frequency far enough out of range to where the two
    do not effect each other.

    I usually end up setting the CRT frequencies to 72Hz, or higher if they
    are capable. The difference is instantly noticable, at least in my
    experience.

    Sorry for the long reply. I hope it helps! :)
    Malware Killer, Sep 17, 2006
    #3
  4. Guest

    On 16 Sep 2006 18:35:13 -0700, "Malware Killer" <>
    wrote:

    > wrote:
    >> I just put together a new computer desk with a hutch. I was thinking of getting
    >> a fluorescent light to put up inder the hutch so at night I don't have to have
    >> the big ceiling light on. Then I started to wonder if a fluorescent light would
    >> be a problem near the computer or monitor. I'm thinking of either the flicker of
    >> the light being a problem looking at the monitor itself or the ballast being a
    >> problem near the computer tower. Thanks.

    >
    >Office workers have suffered because of the fluorescent lights in their
    >respective offices.
    >Wikipedia does a good job explaining why as follows:
    >
    >"Fluorescent lamps which operate directly from mains frequency AC will
    >flicker at twice the mains frequency, since the power being delivered
    >to the lamp drops to zero twice per cycle. This means the light
    >flickers at 120 times per second (Hz) in countries which use
    >60-cycle-per-second (60 Hz) AC, and 100 times per second in those which
    >use 50 Hz. This same principle can also cause hum from fluorescent
    >lamps, actually from its ballast. Both the annoying hum and flicker are
    >eliminated in lamps which use a high-frequency electronic ballast, such
    >as the increasingly popular compact fluorescent bulb.
    >
    >Although most people cannot directly see 120 Hz flicker, some
    >people[1][2] report that 120 Hz flicker causes eyestrain and headache.
    >Dr. J. Veitch has found that people have better reading performance
    >using high-frequency (20-60 kHz) electronic ballasts than magnetic
    >ballasts (120 Hz).[3]
    >
    >In some circumstances, fluorescent lamps operated at mains frequency
    >can also produce flicker at the mains frequency (50 or 60 Hz) itself,
    >which is noticeable by more people. This can happen in the last few
    >hours of tube life when the cathode emission coating at one end is
    >almost run out, and that cathode starts having difficulty emitting
    >enough electrons into the gas fill, resulting in slight rectification
    >and hence uneven light output in positive and negative going mains
    >cycles. Mains frequency flicker can also sometimes be emitted from the
    >very ends of the tubes, as a result of each tube electrode alternately
    >operating as an anode and cathode each half mains cycle, and producing
    >slightly different light output pattern in anode or cathode mode. (This
    >was a more serious issue with tubes over 40 years ago, and many
    >fittings of that era shielded the tube ends from view as a result.)
    >Flicker at mains frequency is more noticeable in the peripheral vision
    >than it is in the centre of gaze."
    >
    >If the fluorescent lights alone cuase eye strain and give workers
    >headaches, imagine staring at a CRT monitor that is flickering at a
    >frequency close enough to the bulb's frequency (60Hz - 50 Hz) to create
    >a "wave effect?" It becomes nauseating after a while.
    >
    >Fortunately, those users who have fluorescent lighting and CRT monitors
    >can adjust the CRT's frequency far enough out of range to where the two
    >do not effect each other.
    >
    >I usually end up setting the CRT frequencies to 72Hz, or higher if they
    >are capable. The difference is instantly noticable, at least in my
    >experience.
    >
    >Sorry for the long reply. I hope it helps! :)


    Thanks for the replies thus far. Since there's mention of a CRT monitor, I
    thought I'd mention that I have a ViewSonic 19" LCD monitor, so I guess I
    needn't worry about the monitor problems?
    , Sep 17, 2006
    #4
  5. Whiskers Guest

    On 2006-09-16, <> wrote:
    > I just put together a new computer desk with a hutch. I was thinking of getting
    > a fluorescent light to put up inder the hutch so at night I don't have to have
    > the big ceiling light on. Then I started to wonder if a fluorescent light would
    > be a problem near the computer or monitor. I'm thinking of either the flicker of
    > the light being a problem looking at the monitor itself or the ballast being a
    > problem near the computer tower. Thanks.


    I've found that the latest compact fluorescent bulbs (the direct
    replacements for traditional filament bulbs) work well with computer
    screens - they don't seem to hum or to flicker or cause eye-strain or
    headaches for me, and they don't get as hot as filament bulbs.

    There are also small LED lamps that can be powered from the computer's USB
    socket, and are adequate for lighting the keyboard.

    --
    -- ^^^^^^^^^^
    -- Whiskers
    -- ~~~~~~~~~~
    Whiskers, Sep 17, 2006
    #5
  6. thanatoid Guest

    wrote in
    news::

    > I just put together a new computer desk with a hutch. I was
    > thinking of getting a fluorescent light to put up inder the
    > hutch so at night I don't have to have the big ceiling
    > light on. Then I started to wonder if a fluorescent light
    > would be a problem near the computer or monitor. I'm
    > thinking of either the flicker of the light being a problem
    > looking at the monitor itself or the ballast being a
    > problem near the computer tower. Thanks.
    >
    >


    I have between 3 and 7 lamps of various sizes in every room in
    the house, and I turn on the one where I am at the time. I
    almost NEVER use the main ceiling light. Way too much light and
    unnecessary. I can only be in one place at one time.

    Fluorescent lights are a horrible invention suitable for slave
    camps and warehouses, and the tiny new mini-ballast "energy
    savers" are only a little easier on the eyes, and a scam, IMO.
    No government or manufacturer is REALLY interested in saving any
    energy, OTOH they LOVE selling expensive stuff they can claim
    will do so. I am sure someone can provide a 30 page long
    document proving how completely wrong I am and what an
    incredible boon to humanity they are, but I am not going to
    waste time reading it.

    Why not just get a $15 gooseneck or architect-style desk lamp
    and use a 25W bulb for low light and no heat?
    thanatoid, Sep 17, 2006
    #6
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