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OK, several pics, of a failed "curly tail" CFL, bought from Home Depot, their older "nameless brand name". Note that there is NO heatsink whatsoever on the devices. Also NO air vents of any consequence in the case.
The design seems to be essentially a type of "Royer" oscillator, or other "flip-flop derived" oscillator, as there is a small toroid, a larger inductor or transformer, and a pair of transistors with no discernible drive circuitry or control IC. The small toroid might reasonably be assumed to be the saturating inductor.
Once device catastrophically failed, splitting its case wide open (pic3), and heating/burning several other components (pic 2, etc).
A hole was apparently also burned in the tube. In the last picture (see the second post below, bless this BBS program.......with a brick) there is visible a hole in the tube near the base, at which point the tube cracked through. The hole may have been made by the filament getting full voltage and burning out, then arcing, generating enough heat to melt the glass locally. The pressure difference may have made the hole through the melted glass. It probably cracked when it cooled.
This one actually failed fairly cleanly, without fanfare... I smelled it, and it was not acting right, although it was still lighting. However, it seems that it SHOULD have totally quit with the damage it sustained internally. It is NOT right that it should have continued to "work", without blowing an internal fuse, or the like. It could only have been lighting by a small current going thru due to 60Hz leakage.
The other one (so far) shot out sparks, and might have caused a fire if not seen and shut off. I haven't cut it open, I'm saving it as evidence. I needn't have cut this one open, apparently they are only "snapped" together, and are not glued or positively held.
The one positive thing I see is that they didn't suffer a breach of the case. The plastic must be fairly good at resisting heat
The design seems to be essentially a type of "Royer" oscillator, or other "flip-flop derived" oscillator, as there is a small toroid, a larger inductor or transformer, and a pair of transistors with no discernible drive circuitry or control IC. The small toroid might reasonably be assumed to be the saturating inductor.
Once device catastrophically failed, splitting its case wide open (pic3), and heating/burning several other components (pic 2, etc).
A hole was apparently also burned in the tube. In the last picture (see the second post below, bless this BBS program.......with a brick) there is visible a hole in the tube near the base, at which point the tube cracked through. The hole may have been made by the filament getting full voltage and burning out, then arcing, generating enough heat to melt the glass locally. The pressure difference may have made the hole through the melted glass. It probably cracked when it cooled.
This one actually failed fairly cleanly, without fanfare... I smelled it, and it was not acting right, although it was still lighting. However, it seems that it SHOULD have totally quit with the damage it sustained internally. It is NOT right that it should have continued to "work", without blowing an internal fuse, or the like. It could only have been lighting by a small current going thru due to 60Hz leakage.
The other one (so far) shot out sparks, and might have caused a fire if not seen and shut off. I haven't cut it open, I'm saving it as evidence. I needn't have cut this one open, apparently they are only "snapped" together, and are not glued or positively held.
The one positive thing I see is that they didn't suffer a breach of the case. The plastic must be fairly good at resisting heat
This cr-p is amazing and the public sits there and lets it be shoved down our throats.
) but for the amount of light you get for the energy they use, they are a dramatic improvement over incandescents.
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