Strange CFL

[JIMMIE]

One of the CFL light s in my bathroom was out so when I touched it it came on for a moment. Figured it may be loose in the socket so I screwed it out and back in and it worked for a minute or two and went back out. OK enough of this, time to get a new lamp so I take it out and while Im walking to the laundry room to get a new CFL the thing lights up in my hand for just a flash. Being an electronic tech I understand that there is probably a capacitor charged up inside combined with a loose connection but that line of reasoning didnt click in as fast as tossing it across the room to get rid of it. I was wondering if anyone else has experienced a bulb lighting while out of the socket.

Jimmie

[JIMMIE]

One of the CFL light s in my bathroom was out so when I touched it it came on for a moment. Figured it may be loose in the socket so I screwed it out and back in and it worked for a minute or two and went back out. OK enough of this, time to get a new lamp so I take it out and while Im walking to the laundry room to get a new CFL the thing lights up in my hand for just a flash. Being an electronic tech I understand that there is probably a capacitor charged up inside combined with a loose connection but that line of reasoning didnt click in as fast as tossing it across the room to get rid of it. I was wondering if anyone else has experienced a bulb lighting while out of the socket.

Jimmie

[The Daring Dufas]

Must have produced a time paradox also. Are there any powerful RF sources nearby? *snicker*

TDD

[snotty]

Used to happen to Bobo the clown a lot...

[Tony]

Only when it was in Uncle Fester's mouth.

[mkirsch1]

A built-up static charge can cause a fluorescent bulb to light in your hand with no visible source of power. Did you happen to scuff across a shag carpet in your feetie pajamas, or rub a balloon in your hair?

[Kurt Ullman]

In the mists of my youth I remember you could get some bulbs from the back of comic books (along with the X-ray glasses and ventriloquist instructions) that would lite up when you put some aluminum foil on the bottom. This is also how I figured out that you shouldn't put AF in your mouth in an attempt to mimic Uncle Fester.

[Jeff The Drunk]

If you were an electronic tech you would know that the ballast in a CFL does not contain capacitors capable of storing enough energy to fire the lamp on its own. If your story is true which I doubt, the only possibility for lighting a fluorescent tube in your hand is static electricity or RF energy. Static electricity still needs a discharge path through the lamp tube and since you don't mention touching anything with the lamp tube this is not likely. An RF field of sufficient energy and close enough in proximity would not need a discharge path. But this would require you to stand near a transmitting antenna. So unless these requirements were met your story is not plausible.,

[Doug Miller]

Another case of theory colliding with reality and coming out on the losing side... One -- just one -- of the four CFLs in the ceiling fixture in our master bedroom will flash visibly about 20 seconds after the fixture is turned off. The time interval is just long enough to lie down in bed after flipping the switch. The flash isn't anywhere near full brightness, but it's plainly visible in a darkened room.

So I find Jimmie's post entirely plausible, and yours ... about par for the course from you.

[Mark]

every CFL i have opened contains a large electrolytic filter cap that can easily hold sufficent energy to flash a lamp..

Mark

[Jeff The Drunk]

Ok dimwit. Here is a schematic of a CFL ballast. The only electrolytic (1 of 2) that would be capable of firing the lamp after the source is shut of is C4 a 10 microfarad 400 volt electrolytic cap. Problem is that it's going to bleed off quickly in that circuit and doesn't have the current capacity (20 watts) to fire the FAN7710N. Remember the filaments need to light first in order for the gas to ionize long enough to be seen.

I will however rescind my "not plausible" statement since it is worthy of a miniscule amount of belief. And not because you happen to limp along into the thread and offer your observation and expect it to be believed especially when you were also motivated to insult. Had that not occured you might have gotten away with your bullshit story.

[Doug Miller]

Like I said... theory collides with reality, and comes out on the losing end. Your imagination to the contrary, it does happen.

Your nickname is clearly accurate.

[Jeff The Drunk]

Losing end of what? I haven't lost anything since you've not proven anything except your lack of the ability to do much but chortle on and on repetitively so about some kind of theory and reality colliding.

Actually it's your imagination getting the better of you.

My nickname is that of a talk show character and does not represent me in real life. I only use it to provoke fools like you into dancing for me.

[Jeff The Drunk]

Ok then explain the circumstances that need to occur in order for the lamp to flash 20 seconds after it is removed from its source voltage?

[LSMFT]

Rub any fluorescent and it lights. I had a CFL that wouldn't light in a basement ceiling light but would work in a lamp. It did not like to be upside down.

[The Daring Dufas]

OH GOD! You wouldn't want to see me dance. Tell me Jeff, would you think it would be possible that the fellow was walking across carpet and the flash could have been caused by a static discharge? I have touched florescent lamps before and gotten a flash from them and the only explanation had to be static electricity. I don't think I'm a significant source of ionizing or non-ionizing radiation. I can remember back in the good old days of CB radio pulling my van under a dark canopy at a service station that had 8' florescent lamps that would light up every time I keyed the transmitter. Perhaps it was the 200W linear amplifier between the radio and antenna. *snicker*

TDD

[Jim Yanik]

Jeff The Drunk wrote in news: [e-mail]:

I took apart a cheap CFL and it's "ballast" is actually an inverter. There's two 4uf/250V caps right on the input configured as a V doubler,and a tiny transformer driven by two transistors as the inverter. I suppose it could fire up and ignite the tube if a cap had a loose connection.

[Jeff The Drunk]

Well if the OP was holding it in his hand while charging his body I would think his entire body would be at the same potential as the CFL. You can charge a glass rod so why not assume the glass CFL envelope charged at the same potential as the body? We are talking STATIC electricity and certain rules apply.

Like I said in my first reply there has to be a discharge path for static electricity. Did you not watch your Mr Wizard on the tele?

As far as charging florescent lamps go I did them on a 1.5 KW Ameritron AL-1500 ham amp and a longwire antenna. They glow real bright if you hang them from the longwire :)

[Jeff The Drunk]

Yes that is a possibility but with a discrete component inverter instead of a PWN/MOSFET AC-DC inverter like the Fairchild 7710N so much has to happen in the circuit as far as resonance and ac shunting/diode switching etc that a momentary contact with a cold soldered cap just seems unlikely. But would 4uf be enough to start the mosfets and the rest of the PWM circuit? I doubt it.

Like I said I will consider this remotely possible but I've never seen it or heard any other discussion of it. Yes I know that's not saying much with the zillions of CFLs out there but it's all I can say and this is the end of the road for me. Case closed.

[The Daring Dufas]

There's nothing like watching the blue glow of the tubes in your linear amplifier whilst gabbing to the either. It was fun to freak out people by touching one end of an F72T12 8' lamp to my antenna and having it light up the night. I used to sell Fireflys, those little red neon lamps to clip on the end of 1/4 wave whips, do you remember those things? I haven't played around with CB stuff in 30 years, I wonder what it's like now? I stayed with boring commercial two way and broadcast gear where you can't have too much fun without getting into trouble. Darnit! I guess The Interweb will have to do.

Wait! There IS talk radio! *snicker*

TDD