# Problem using a CFC bulb in my Dusk-to-Dawn porch light



## wahoowad (Jan 28, 2008)

Brought home my first batch of CFC 13W bulbs. I put one in my front porch light as I like to leave this on and let my dusk-to-dawn adapter turn the power on and off, depending on daylight/nighttime. But the CFC pulses quickly and I have determined it is the adapter causing it (doesn't do it when I screw bulb directly into fixture). I don't recall the adapter having any kind of power modulation feature - it is just supposed to turn the light on at dusk and off at dawn. So is this an issue with using this type of bulb in the adapter, or is maybe my adapter bad? I never noticed it with the standard bulb in it although I know the bulb seemed dimmer than it should have been.


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## DiscoInferno (Jan 28, 2008)

1.  I sure hope you mean CFL!  The ozone layer doesn't need any more CFC's.
2.  CFL's start out dim and don't reach full brightness until they warm up.  When used outside, that can take a long time or never happen depending on the fixture and temperature.
3.  A straight on-off light-activated switch should work; they sell one at Home Despot that is specifically labeled for CFL useage.  But anything that causes a voltage drop (like dimmer-type controls) will cause CFL's to flicker/dim/buzz.  (A dim incandescent bulb suggests this is the issue.)  If you have an AC meter, compare the "on" voltage of the socket to that of the adapter.


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## wahoowad (Jan 28, 2008)

Yeah, I meant CFL. Sorry.

Actually the one's I used today start off surprisingly bright and have stayed bright. In fact, the two I used in my kitchen ceiling light are putting out more light than the 2 60W clear bulbs I replace. That is great as I needed a bit more light in there.

I think my dusk-dawn adapter is bad. I'll look for that CFL-specific on at Slowes.


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## mayhem (Jan 28, 2008)

Check your fixture's operation with a normal bulb and see if it has an auto dimmer.   Many of the dusk to dawn fixtures dim the light to about half power when they're in D-D mode and the light sensor isn't seeing anything in range...my last few were like this.  Normal CFL's don't dim, though you cna buy dimmable CFL's.

Just a thought.


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## Corey (Jan 28, 2008)

Even your dusk/dawn socket is probably using a triac to turn the light on and off.  That is to say - it is not physically throwing a switch or relay, but relying on an electronic component to do the switching (actually, the same component a dimmer relies on to do the dimming).  

With the AC line voltage, it takes the triac a small, but noticeable amount of time to 'switch on' each time the voltage crosses zero and changes direction.  This 'switch on delay' can be electronically controlled - longer  delay time means more dimming for an incandescent lamp, and more flickering for a fluorescent lamp.  But even in a maximum 'on' state, they are still a slight delay on every AC cycle.


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## AndyD1480 (Jan 29, 2008)

I'll tell you, I've had the same experience with those bulbs. For whatever reason they really dont like the auto-on adapters. They flicker like crazy. I've also tried ones that werent supposed to do that, and they still flickered. 

I'd love to use less power on those lights. They're the only ones all night, every night!


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## Highbeam (Jan 29, 2008)

CFLs and photocells don't mix. I don't know why but the photocell package said so when I went to replace what I thought was a bad photocell. They make entire flourescent or flourex fixtures that are D to D and use an integral photocell for on/off duty. That's what I ended up getting, the flourex makes even more light per watt than the CFLs but the fixtures aren't as pretty.


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## billb3 (Jan 29, 2008)

There are (unfortunately, would be nice if they were marked or marked better) some dimmers that even dimmable CFLs don't like and some switches CFLs don't like, too.
I haven't had much luck with  motion detectors and CFLs either.


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