Avon
Lv 7
Avon asked in Science & MathematicsPhysics · 1 decade ago

Energy saving light glows every 30 seconds when turned off?

I’ve a standard energy saving light bulb in a room where I keep my PC, there are no windows in the room, but I’ve noticed the light bulb glows every 30 seconds when turned off? At first I thought it was a reflection from a LED on one of the items of computer gear, so I turned everything off, still happens? No mobile phones or wi-fi / Bluetooth devices / known transmitters in house, so what is making this bulb glow?

11 Answers

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  • Anonymous
    1 decade ago
    Favorite Answer

    Could be radar if you are near an airport.

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  • 1 decade ago

    If the mains isn't coming on periodically, which it probably isn't, then the radar explanation if probably the most likely cause. Early warning radar and radar sweeps from nearby airports can cause this. The other possibilities are -

    mains-borne networks - these use high frequency fm signals to transfer network data down the mains cables and can cause problems such as this. I've even seen it when the neighbours have a main network, even though I haven't!

    plasma / lightning lamps - these can generate HUGE rf fields that can be felt up to 10 feet away ! If you've got one of these, try holding a neon lamp close to it and see the light show!

    neighbours' wireless network - these can transmit up to 300m !

    near-by cellular phone masts - miles !

    near-by radio masts - 10's to 100's of miles depending on the power

    There's probably many other possible causes, when looking just remember, for the bulb to glow the r.f. field must be high frequency.

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  • 1 decade ago

    The most likely cause IS some form of electromagnetic radiation

    Radio Transmitter,

    Micro waves

    Telephone mast

    Radar

    ( any wire less / remote appliances ?)

    They are just fluorescent tubes bent into a different shape

    To get them to LIGHT you need a high voltage to strike them

    To get them to GLOW you need some form of radiation at higher frequency than that of the Mains ( half submerge one in a cup of water or milk and microwave for 30 sec ...watch through the glass door ..... it will glow from the microwave energy)

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  • 1 decade ago

    Ah! Mine does that too!

    It's most bizzare, but the energy saving bulb in the hallway light flashes every 30 seconds or so also when not switched on.

    But the bulb hasn't blown up or anything, so I figured it wasn't that big of a deal.

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  • Anonymous
    1 decade ago

    Make sure the light is being switched on and off via the live not the neutral. Also check the switch, cable and fitting for any possible tracking to earth.

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  • 1 decade ago

    the radar possibility is interesting.

    most likely, it is drawing a tiny amount of current that makes it light up. so tiny that even the leakage current in the return wire is enough.

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  • 1 decade ago

    Maybe it's whatever it's connected to. try unplugging it. if not there's probably some kind of inductor inside your lamp giving energy to the bulb.

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  • Gene
    Lv 7
    1 decade ago

    You're missing some power source close by. If what you have is true, you have a perpetual motion machine where you get power for free. That's impossible/

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  • 4 years ago

    lola, if bulb gets hot enough, thru filament it glows

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  • SS4
    Lv 7
    1 decade ago

    most likely it is still drawing a small amount of power from the fuse.

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