What’s in a… Compact Fluourescent Lightbulb?

“It came apart in me ‘and, honest Guv!”

First, a quick “Hello!” to everyone and a quick “Sorry!” for not having written anything for a while. I’m not sure where the time goes but, since my last post, I have been doing ‘things’ which seem to include not finishing the first draft of my third novel or figuring out what to do with the bits from… well what follows. I did build a snow dog…

A Miniature Snowzer

… but that probably isn’t relevant here so forget I mentioned it.

Whilst playing with Sam, a real flesh-and-blood dog, a light bulb was mortally injured and had to be put down, well, removed from the light fitting. Basically, the toy that I was throwing hit the hallway light and knocked the bulb out onto the carpet, where against all expectations and possibly a few laws of physics, it shattered. The bulb, not the carpet.

Opening the case is a Saw Point

Having cleaned up the glass (nasty in itself because of the thin mercury coating on the inside), I turned my attention to taking the rest of the thing apart. Actually, this was something I was intending to do and have had an old defunct bulb on my workbench for about a year now. Clearly this was a message from the universe telling me to stop waiting!

I had to saw the case in half – apparently other makes can be persuaded to open much more easily. This one, a cheap IKEA bulb, was moulded closed, presumably because it is easier to manufacture that way.

How the tube is connected

The Board with the nifty bits on

 

 

 

 

 

 

 

 

The components in this bulb will be similar to those in every type of lamp like this – even the mini CFL things we briefly used (they heat up so much that the holders warp and then they don’t work – a design flaw if ever there was one!). I think there will be a few slightly different components in the LED bulb that I bought and doesn’t work properly (unfortunately, the company I bought it from have failed to reply to my requests for a replacement).

In answer to the “What’s in” question…

Surprisingly, most of the components are standard sized ones – only a few resistors are the surface-mount variety, which is good because they are virtually unusable for hobbyists such as myself (you need a specialist soldering iron to remove them and re-use them easily).

From the left, the two things with three legs are transistors, then there are some inductors (coils of wire), a big capacitor (stores electric charge), five diodes, 3 small capacitors (store tiny amounts of charge) and a diac (that small blue thing, but probably wasn’t the one Suzanne Vega sung about). Below that is the circuit board and three surface-mount resistors.

There is a similar haul of components in the small CFL

The daft thing is that these electronic bits could be built into a holder that screwed into the light fitting (or just built into new light fittings), removing the need to have to keep building them. The bulbs would be easier to recycle then – just separate the base from the glass, and process the bits accordingly. At least one company can remove the mercury coating to produce safe, re-usable glass (well, it says so on their website so it must be true). I believe business premises have this arrangement in some places. Why not for the majority of users? Old fluorescent tubes had replaceable starters, after all.

I was hoping to have designed and built something using just these components and perhaps a solar cell, but haven’t managed to make something that works – yet. Watch this space!

oOo