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Author Topic: Why do energy saving lightbulbs "flash" when off?  (Read 7179 times)

Offline chris

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I have several energy saving lightbulbs in my home. But I had to remove the one from my bedroom because it was keeping me awake! When it was turned off it would intermittently (but regularly) emit brief flashes of light.

I asked an electrician in South Africa about this and he suggested some kind of earth-leakage problem, or a floating potential on the neutral line.

What does everyone here think?

Chris


 

Offline LeeE

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Why do energy saving lightbulbs "flash" when off?
« Reply #1 on: 24/10/2009 22:53:45 »
Dunno, but I've got one bulb, out of several, that also does this.  I haven't bothered with swapping the bulb with another to see if the behaviour moves because it's in my living room and doesn't bother me, but you could try doing so, to tie down whether it's the bulb or the wiring.
 

Offline Madidus_Scientia

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Why do energy saving lightbulbs "flash" when off?
« Reply #2 on: 25/10/2009 02:42:03 »
A friend of mine had a similar problem, I found this;

Quote
The phenomenon of lamps starting to flicker after switch-off is caused by a small current which continues to flow through the lamp. This causes the lamp trying, unsuccessfully, to switch on again.
(The low current continuously charges the built-in capacitor; if the charging is completed, the capacitor will initiate a pulse to start the lamp, similar to normal switching of the lamp; however, since the current is too small, the discharge inside the lamp is not strong enough; hence the lamp will extinguish, after which the same sequence will be repeated).

There can be several reasons for a continuous small current:
· the lamp is operated on dimmer or electronic switches (the latter including photocells, timer devices, dusk-to-dawn sensors, and switches with a built-in ‘neon’ orientation light).
Our lamp packaging contains an explicit warning, NOT to use the lamps in these applications.
· The wiring in the house is not optimally isolated, leading to a magnetic field, resulting in a small current flow.

We are investing alternative lamp electronics designs.
Until then, we advise consumers, NOT to use electronic energy savers in the specific luminaries/fixture where the phenomenon occurred.

From June 2003, our PLE Master lamps are equipped with an electronic device, which solves the problem of continuous flickering in installations with a neon switch.
Still, lamps should not be operated on dimmers, movement detectors and timers.

from
http://forums.lighting.philips.com/viewtopic.php?t=105
 

Offline techmind

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Why do energy saving lightbulbs "flash" when off?
« Reply #3 on: 31/10/2009 14:48:14 »
Is the offending flashing bulb in a lamp / circuit with a true mechanical switch, or is there an 'electronic' switch (like a lamp where you merely touch the base to turn it on or off)?

It is well-known that CFLs will flash when 'off' if used on electronic controllers, including motion-sensing fittings, light/dark sensing fittings etc, and CFLs are not recommended for these.
 

Offline LeeE

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Why do energy saving lightbulbs "flash" when off?
« Reply #4 on: 31/10/2009 21:19:16 »
The single one of mine that flashes is attached to a simple mechanical switch.  It only flashes after being switched on for a period of time, before being switched off, and eventually stops after five to ten minutes or so.  It doesn't continually flash and seems to need to be 'charged-up' for it to happen.
 

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Why do energy saving lightbulbs "flash" when off?
« Reply #4 on: 31/10/2009 21:19:16 »

 

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