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Author Topic: Why does my energy saving light bulb flash when not switched on?  (Read 53375 times)

Offline graham.d

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Geezer, Syphrum, Sean - this probably is the explanation (in fact I can't think of any other) although I did not think the wiring was done in this way - I confess to not bothering to go into the loft to find out, or even looking to see how many cables are behind the switch which may be easier. Had there been two switches operating the light (as alternatives) then this is always the case and there could be coupling from a Live wire to the switched out part of the Live side of the switch but I had not thought this likely with a single switch. However I see that it makes sense as it means only one cable is needed to be in the wall.

Clifford, yes, I have seen problems with dimmers and these lamps before, but there is no dimmer involved here.

I will look behind the switch when I'm next home to see, but I reckon you have the right explanation. Thanks chaps. I can now go back to counting sheep rather than light flashes.
 

Offline Geezer

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If that's what's causing it there is not too much you can do about it, although, I suppose you could always wire a small incandescent bulb in parallel with the CFL!
 

Offline syhprum

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There are two simple ways to stop it one is to put a resitor (100K 1watt) across the lamp or replace the switch with a change over type that grounds the line feed to the lamp in the off position (if a ground or neutral line is handy)
 

Offline graham.d

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Actually it's no more disturbing than the flashing LED on a smoke detector. I was really just curious as to the cause.
 

Offline syhprum

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There is a slightly more technical solution for those in the USA that have a bi-phase 110/220 volt main.
The reverse phase can be fed to the lamp via a capacitor of equal capacitance to that of the switch cable neutrolising the effect.
Make sure the capacitor can withstand 220v or there may be a bang
« Last Edit: 04/04/2012 09:52:38 by syhprum »
 

Offline Geezer

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There is a slightly more technical solution for those in the USA that have a bi-phase 110/220 volt main.
The reverse phase can be fed to the lamp via a capacitor of equal capacitance to that of the switch cable neutrolising the effect.
Make sure the capacitor can withstand 220v or there may be a bang

I think I prefer the changeover switch!
 

Offline Geezer

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Actually it's no more disturbing than the flashing LED on a smoke detector. I was really just curious as to the cause.

Rats!
 
I was hoping to make a killing on Skymall with "Geezer's Patent CFL Anti-flicker Resistor Technology".
 
Simply attach this remarkable invention to your CFL before you screw it into the socket.  Only $19.95 for a pack of five.
 

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