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Saturday, 5 May 2007

CF light bulb spookiness

Only days into the big switch from incandescent to compact fluorescent light bulbs, I've been forced to remove the bulb from the ceiling fixture in Joshua's room. He was seriously freaked out by it.

There is something very strange about the way the new bulbs are behaving here. At night, once your eyes have adjusted to the dark, all of the ceiling-mounted bulbs can be seen to give off small, regular pulses of light.

For a while I thought it might be due to some kind of energy build-up due to radio waves (we have a huge AM radio tower just down the road) but bulbs that aren't in the sockets don't flash. I suspected the ceiling fans could have been causing some kind of interference but it happens even when all the fans are off.

Joshua noticed it on Thursday night and it terrified him. Since I don't know what causes it or how to stop it, I had no choice but to remove the bulb.



Iain Robertson said...

You know, I'll hazard a guess that it is the AM tower up the road from you (I believe that's the 612kHz ABC transmitter (in which case, its amplifiers produce around 10kW of power, for a very rough EIRP of 18kW).

Why don't your fluoro lights flash when not in the sockets? There's no antenna of any substantial length connected to them when they're sitting bare; when they're in the sockets there'll be at least a couple of metres of copper wire connected to each terminal (i.e. between the electrical switch & the bulb socket).

That's my guess at least. It might be possible to put in some kind of RF isolator or low-pass filter to stop the effect, if indeed such systems exist for 240V house supplies.

TB said...

Thanks Iain. I had wondered about the antenna affect but as I don't know much about AC and RF I didn't want to speculate too much.

I might try switching the mains power off completely once it gets dark and see if the lights still pulse - that would be a fairly good indication that radio waves are the culprit. Might even be fun to run some wire to nowhere and see if it can induce some light from a bulb.

Will let you know what I discover.