Dusk to Dawn Bulbs

Maybe the light sensor is seeing the lamp's own light reflected back at it, and thinking its daylight. Solution would be to shield the sensor from the light from the bulb as far as poss.

NT

Elimination,have you tried them elsewere in the house ie another room

On Mon, 30 Jul 2007 13:54:43 +0100 someone who may be "Ed" wrote this:-

How rapidly do they switch on and off?

If this is less than say every five minutes they are probably seeing the light from the lamp.

probably wont work in a normal pendant fitting near a window

I had some hassle with these - if you mean the energy saving ones. Firstly, they only seem to come down as low as 15W, which is much too bright and glary for what I was using them for - lighting an outside flight of steps. They were also very expensive and very short lived.

Eventually, I gave up on the built in sensors, and just bought a single photo switch of the type used in street lights, and it has now been reliably turning on and off a series of 4, 7w cfls for a couple of years, with no lamp failures yet. Very good.

I've always been puzzled as to how these things work. If their own light can turn them off, how do they ever turn on? Is it a different wavelength or something?

On Mon, 30 Jul 2007 22:20:15 +0100 someone who may be "The Medway Handyman" wrote this:-

Their own light can turn them off if it is reflected back from the luminaire to the sensor. This can happen with the type of luminaire that has metal bands around a glass envelope.

I would use a remote sensor if doing this with a table or standard lamp, which appeared to be what the original question was about.

throughtout the week.

Indeed. Ensure it points as towards the window as poss, reduce lampshade reflection, and if still necessary glue a bit of black card on to reduce light from the lamp falling on the sensor.

As has been said, sensor built into bulb isnt very smart as you have to repeatedly replace the sensor every time the bulb goes. I dont know why anyone buys them.

NT