Everyone is familiar with the Compact Fluorescent Light or CFL. Since they appeared on the scene they have invaded our homes and pushed the poor old incandescent bulb nearly to extinction. Most of the CFLs that I have purchased had 5 year guarantees and bragged about 5000 hours of service. Unfortunately based on the number that have failed I believe that this is a bit of an exaggeration. A while back I stopped throwing them away outright and started salvaging them for electronic parts. Here is a failed bulb that I am about to crack open.
I open the base of the bulb by putting a flat screwdriver in the crack and twisting. Sometimes it is necessary to tap the screwdriver into the plastic before I twist. While the glass tube is attached it is a good idea to handle the bulb with a pair of work gloves. If the glass breaks it would be dangerous and if you slip with the screwdriver the gloves will protect you. Once the base is open you will find a small circuit board attached to the base with two wires and also to each of the tube ends with two wires.
Cut the wires to the base and the tube and dispose of the base and tube. Be sure to save the high temperature pieces of spaghetti that cover the wires as they can be very useful for future builds. Sometimes there will be a small inline 2A fuse also. The next step is to clamp the circuit board and begin to remove the parts with your solder iron. Nearly all the boards I have encountered have the same basic parts on the board. They vary slightly from manufacturer to manufacturer but almost always there is a similar bill of materials.
Here is a layout of the parts that I got from the board I took apart this afternoon:
In this case, besides the usual capacitor, resistors, spaghetti, inductors, and diodes, there are a couple of power NPN transistors with built in flyback diodes. I have used these in projects to drive motors and LEDs. If you need to there is a hole to heat sink them. Also in the haul is a BR-3 trigger diode that can be used in conjunction with an SCR to make a motor speed control or a light dimmer for incandescent lights. The Electrolytic in the middle of the picture has a 200 VDC rating which is a little high for my needs but who knows what I may try to build next week. There were also (7) 1N4007 diodes which are rated at 1kV 1A. There is a small 0.2 mH inductor and a larger 1 or 2 mH inductor. In most of the units I have salvaged the components are all marked for values though the transistors are OEM and usually will not be identifiable except by analysis by a component tester. There is also usually a small toroid transformer that can be used as is or rewound for other uses.
Since this is a failed bulb that we are salvaging I usually test the components and discard any that do not test properly. The bulbs however seldom fail due to component failure. It is usually a bad filament in the tube or a solder joint that has crystallized and cracked.
You will not get rich salvaging bulbs but if you like playing with electronics and want a relaxing 45 minutes this is not a bad way to go and you get some new free components to play with to boot.
John
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