If you have already read my articles on digital ballasts, then you probably already know that your normal energy saving bulbs are compact fluorescents (CFLs). You are also probably aware that in order to make these bulbs functional in "normal" bayonet and edison screw sockets, they had to put the CFL and ballast together in one package. What this means is that each CFL has a ballast which can be reused to both save money and the environment (if thats your thing. After all, why throw away perfectly good hardware?).
In my personal experience, I have found that only one CFL that burnt out so far was due to the ballast. All of the others were due to wear and tear on the lamp itself. This means that it is highly likely that you can reuse the ballast from your broken CFL's to attach to new lamps.
Reasons for doing this:
Disclamer: Before we get started, understand that we will be dealing with high voltages here, sometimes in excess of 500V. This can kill you, and I am not responsible for anything that may happen to you or anyone else based on what you read on this site. Make sure you are comfortable with dealing with high voltages and you know how to protect yourself before attempting any of this.
This is the CFL I will be using as an example. It is a 14 Watt Genie brand by Philips:
It's lamp has failed (as you can see from the blackened ends) but the ballast is most likely still in working order. We start by prying open the two halves (you can see the line around the CFL where the two bits come together). After much prying, the two halves come apart:
After the prying, you have your two halves, with the ballast PCB in the middle. The two red wires go to the plug at the bottom, which have to be cut off to remove the PCB:
And the ballast removed from the CFL:
The two red wires are for 240V AC input from the mains, and the 4 pins on the right are for the fluorescent lamp. They are split into two sets. One goes to one side of the 4-pin lamp, and the other set on the other side of the lamp. For testing we just attached crocodile clips, as so:
The lamp is a standard 4-pin CFL I bought off ebay (pack of 10 for 1.20 GBP). Here it is with power applied and initial ignition:
And thats it really all that there is to it. I would recommend you put it a insulated box and properly wire the pins together. Below are some examples I have already done.
Upon moving to a new flat with my family, the room that I got had a light fixture that had a 100W bulb while it was rated for 40W. I didn't know this so I just turned on the light and went to do some unpacking. Within the 15 or so minutes the fixture had almost totallly melted and the smell was horrible. After this I could not remove the lamp from the fixture, because the plastic had melted around the bulb so I had no choice but to remove the whole fixture and bin it. This left me with no light in the room, so I made a quick one out of an old CFL and a 2D fluorescent lamp that was binned.
The Ballst taken from a 15W CFL that burnt out:
Here it is attached to the 2D lamp for testing. I had already wired the pins to normal wire, and also removed the capacitor and reattached it so it would make the whole thing slimmer:
And first test:
I put it in a plastic box, and placed it where the original fixture was: