Strange CFL

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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.
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I have heard of and a couple times seen CFLs occaisionally flashing dimly from leakage current.
And fluorescents do not necessarily need the filaments to be preheated as a condition of glowing. Ever hear of what in North America is referred to as "instant start"?
I have seen many CFLs like that. And static electricity does easily cause fluorescents to visible flicker in a dark room, even if charge couples capacitively through the glass.
- Don Klipstein ( snipped-for-privacy@misty.com)
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On Apr 18, 5:03 pm, snipped-for-privacy@manx.misty.com (Don Klipstein) wrote:

This wasnt in a dark room the flash was pretty bright, I'm familiar with the tiny flicker you can get from a static charge. This was much brighter than that. My main concern beyond curiosity is that this may be a shock hazard. Not that it would probably hurt you directly but I can imagine someone coming off the top of a ladder because of something like this.
Jimmie
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JIMMIE wrote:

I seem to think that in this case minor static shocked the CFL into utilizing very briefly energy that the main filter capacitor had on hand.
And those bigger capacitors have a substantial rate of slowing down their self-discharge rate as self-discharge prgresses, and they even have stored energy that avoids being entirely discharged by a very brief true short, let alone a partial one.
However, I would question as to a dim flash appearing bright to someone mentally unprepared to expect such a flash.
One thing that I like to mention:
http://members.misty.com/don/xesafe.html
- Don Klipstein ( snipped-for-privacy@misty.com)
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On Apr 18, 9:50 pm, snipped-for-privacy@manx.misty.com (Don Klipstein) wrote:

I made mine dimmly flash for maybe a month, I had maximum static charge when I took of my jacket and entered the house. Over a month it would not be the cap, it was a HD cfl if I remember right.
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On Sun, 18 Apr 2010 21:03:30 +0000 (UTC), snipped-for-privacy@manx.misty.com (Don Klipstein)wrote:

Good for you.

Has nothing to do with holding a CFL in your hand

This wasn't a flicker in a dark room.
Like I mentioned in my last post several days ago I have changed my mind somewhat that a charged smoother cap on the DC bridge side might be able to flash a CFL in your hand IF it was poorly soldered and was fully charged then bumped back into connection. But since most CFLs even rapid starting use a combination cathode/filament I have my doubts. I recently had a rapid or as you call it, "instant" start CFL fail. Guess what? When it failed it would not fire but it did glow orange-ish faintly on the very ends of the tube indicating it does heat the filaments. My contention is there would not be enough current at sufficient voltage stored in the smoother cap to supply the inverter circuit and the filament to make a momentary arc in the tube. if you believe otherwise well good for you we'll just agree to disagree and go on with out lives.
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Only due to visibly glowing/flickering from static electricity having high independence from the CFL's designed starting method. I have high personal experience with CFLs having at least 3 different starting methods.

What are we talking about here?

Glowing faintly orange at the ends and nowhere else is not what in North America is referred to as "instant start".
Please keep in mind that in North America, "rapid start" differs from "instant start" by requiring significant filament heating.

How about a mode other than "arc", even used in commercial practice in many CFLs although quite a minority of them? As in the "cold cathode" ones where "glow discharge" (different from arc, especially a hot-cathode arc) is outright Plan A? I saw very many thousands of CFLs, likely 10,000's of CFLs, of "cold cathode" type last 3 times I was in Las Vegas, in late 2006, 2007, and 2009.
And I have made fluorescent lamps glow spectacularly bright (even if well short of normal brightness) with non-arc discharge, even using fluorescent lamps designed for arc discharge, and I have especially made fluorescent lamps not only visibly glow but also spectacularly glow from static electricity without so much as resorting to the likes of capacitors and Vanm de Graaf generators.
It has been noted that fluorescent lamps at least often have greatest efficiency at currents less than what they were nominally designed to handle. As well as I can remember, it appears to me fair chance that books authored by Elenbaas and the first of the two related Waymouths most notably working in the electric lamp industry (according to the younger one posting into the Usenet newsgroup sci.engr.lighting in my experience) explain that well enough, slight chance only one of those two authors make that case in a book among the ones by them that I have put time into reading over 25 years ago.

- Don Klipstein ( snipped-for-privacy@misty.com)
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Doug, I agree with you. I've see plenty of flashing CFL's operate just the way Jimmie describes. They are indeed capable of storing enough energy to "flash over" briefly - users of X-10, the powerline home automation system, are quite familiar with CFL flashing issues. X-10 leaks a trickle current through the controlled device to detect the user activating the device's built in switch. CFL bulbs absorb this leakage and flash every 1 to 5 seconds from the charge building up through the leak current. You can get a fluorescent bulb to flash just by rubbing the end on some wool, FWIW.
http://blogs.consumerreports.org/safety/2010/04/cfl-safety-ul-report.html says:
"Laboratories (UL) has just released its findings on CFLs and concludes the bulbs are safe. Issues like flickering, flashing or unusual noises don't indicate fire or shock hazards. Those foibles are the result of using CFLs with fixtures and lighting controls (switches, sensors and dimmers) that were designed for incandescent bulbs."
http://en.wikipedia.org/wiki/Compact_fluorescent_lamp says:
"Some timers rely on a connection to neutral through the bulb and so pass a tiny current through the bulb, charging the capacitors in the electronic ballast. They may not work with a CFL connected, unless an incandescent bulb is also connected. They may also cause the CFL to flash when off. This can also be true for illuminated wall switches and motion sensors"
-- Bobby G.
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every CFL i have opened contains a large electrolytic filter cap that can easily hold sufficent energy to flash a lamp..
Mark
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On Wed, 14 Apr 2010 09:33:05 -0700 (PDT), Mark

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?
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JIMMIE wrote:

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.
--
LSMFT

I'm trying to think but nothing happens.........
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Static charge does it, I had one on a table near my entrance, in winter with dry air I by accident touched it one night comming inside and it lit up, so I left the bulb there and every night for fun I touch it and it lights up with my static buildup.
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On Wed, 14 Apr 2010 17:46:47 -0700 (PDT), ransley

You have an "electrifying personality" and "light up the room" when you enter. :-/
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CFLs are also effected by too high or too low voltages, as a buddy who uses CFLs on a inverter found out.......
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