We try to run compact fluorescents around the house as much as we can to save energy. It typically the right thing to do.
This one died though.
They’re supposed to last much much much longer than a standard incandescent bulb, but I’m not 100% sure in real life. Maybe under lab conditions they do… but… well… I, for one, don’t live in a lab. (Though that would be cool now and then)
The mode of failure is the tube itself breaking.
Now before you think this was caused by simple shock, it wasn’t. Later on, on the inside I was noticing signs of overheating right around where the tube and plastic meet. My guess is the thermal stress of cycling the light got to a weak part of the glass envelope and caused it to break.
This gets to another point: mercury. A common complaint, rightly so really, is that fluorescent bulbs, compact or otherwise, contain the stuff. Mercury is a neurotoxin. The whole saying “mad as a hatter” is because hatmakers were exposed to mercury in the production felt. Since the envelope was already broken and the mercury released into the air (in my house… grrr…) I’m not making it any worse by messing around with it.
At first I tried to take it apart by attacking it with a utility knife. I quit before I cut myself. It was too thick and it would take me all night to hack it open.
Like Norm Abrams always says: wear your safety glasses! The Dremel with the cut-off wheel spins stupid fast. The wheel can shatter if you subject it to any real side-load. Those parts can go all over the place. You don’t want it going into your eye!
From what I can tell this is a pretty convention design. There’s a bridge rectifier on the front-end that produces a real lumpy DC output and a capacitor to smooth it out a tad. Beyond that there’s a simply wound toroidal transformer (not the big red thing), a few transistors and capacitors.
The big red transformer looking thing is actually an inductor.
At first I thought it was since it looks like all the other small transformers I’ve seen in the past. Even the footprint and pads on the bottom look right. That is until you notice it only has two leads! There’s extras in there no doubt to allow swapping of parts specifications depending on the cost any given day.
My guess from looking at schematics people have posted is that this is a variant of a Hartley oscillator but I’m not 100% sure of it.
That’s why this is a part one. :-) I want to take the time to reverse engineer this thing and see how this one is put together!
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