Take apart a Compact Fluorescent Bulb

Step 7 What can I do with the Parts?

If the tube is still good, you can power it with other types of ballasts or inverters. The picture shows a cheap surplus CCFL inverter mounted inside the spiral of a CFL; the bulb now operates on 5V (and runs about 3W...)

If the inverter as a whole is still good, you may be able to use it to power other types of fluorescent bulb. Search the internet for more detailed instructions.

The capacitors, resistors, and diodes may have general purpose applications, if they're good.

To me, the valuable parts are the inductors; it can be difficult to find inductors in typical hobbyist marketplaces, especially in the sort of high-current versions found in CFLs. The toroid can easily be stripped of its original windings and re-wound for other purposes, such as the classic Joule Thief single-cell LED driver. The small inductor looks like it would fit in many "low tech" switching power supply applications, like The Roman Black Switching regulator or this other white LED driver. The large inductor I'm not sure; in the worst case it also provides a compact core that could be re-wound for special purpose applications.

If you don't use the tube, try to dispose of it at a recycling center that accepts fluorescent lights. They may not be too happy to get ... pieces, but they shouldn't mind TOO much as long as the glass is intact.

Comments

[virgo]

Thanks , instructable was very educative.

[joinaqd]

how much voltage would you say the CFL needs to operate?can it work with 330 volts from disposable camera?

[westfw]

Now THAT's an interesting question. CCFL inverters like the one shown tend to provide more than 330V, at least for "ignition", but they don't need much more than 110V to actually run. (The whole "startup" thing is complex in fluorescents.) Disposable camera inverters are not very efficient, and don't put out very much power overall, but it WOULD be neat to get any light at all out of a CFL from a 1.5V battery!

[thermoelectric]

I've tried to use a CFL off a capacitor, It won't work unless you can have a higher voltage to strike it, I used a piece of wire connected to the trigger transformer to light the CFL.....

[qwertyboy]

i've seen joule thief circuits built to power a CFL from a 1.5 volt battery. it's sweet.

[joinaqd]

i got 2 small tube lights from an LCD monitor but i couldnt power it with the circuit board on the monitor..will the tube lights blow off if i powered them from normal 120V CFL? (like if i connected them to the 4 wires on the CFL?)

[westfw]

Hmm. It's probably a bad idea. The tube lights tend to be "CCFL" (Cold Cathode Fluorescent Lamp) technology rather than CFL (Compact ...), and the drivers are rather different. Also, the tiny tubes tend to be much lower in power (~4W) than a normal CFL (11W?) You might try the CFL inverter from one of the tiny candelabra-base bulbs. Carefully. While wearing eye protection...

[joinaqd]

ohh ok..thx for tellin me, otherwise i woulda connected them to the CFL and probbly it woulda exploded in my face.

[JVC-Force]

Very educational post. I want to see following posts with the parts harvested.

[penorama]

I've opened a CFL circuit of a table lamp (here the circuit is not enclosed in the bulb). Trying to repair it, I've messed up the coils while removing from the PCB. Can you advice me how to wind the toroidal transformer? It has three coloured wires wound to it. I can measure the length of the wires, but would like to know the order of winding, etc. I do not have technical background (being a retired accountant), so request you to tell me in lay-man terms. Thanks.

[junits15]

just wind them again and solder them in the appropriate holes.

[The Lightning Stalker]

If anyone else is curious, the only requirement is that the two feedback windings are attached to the bases (or gates if they're MOSFET) of the transistors opposite one another. It depends on the ballast, but it's done either by winding them in different directions or just connecting one of them backwards. It's one of those spatial things that's difficult to explain with words or pictures unless you have experience winding transformers.

[westfw]

I don't know. I'm not really an expert on CFL internals. I think the best bet would be to find a CFL bulb of identical wattage to the tube in your lamp, dissect it (carefully, so as not to damage AND to remember which wires from te ballast go to which wires on the tube) to extract the electronic ballast (the circuit board), and drop that in to your lamp as a module; replacing the old ballast. Be careful, because the old packaging may not be compatible with all those bare wires poking out of the board (other broken fluorescent fixtures I've dissected tend to have the inverter embedded in a solid block of plastic gunk.)

[wolfy_9005]

Depends, mine has 2 wires(i think) wrapped around it. One lot has 13 wraps, the other has 6. Maybe 13, 3, 3.

[greengiant1298]

I really liked the Instructable and never really knew so many thing were in a CFL. But what really interested me was how you were able to get the bulb working with only 5 volts. I, not being very good with circuits, am wondering if this bulb could then be powered by a DC battery? if so, it would make a great instructable.

[Prometheus]

There are portable battery-powered CFL's that have been available for over a decade. In any case, it requires an inverter to use a transformer, or a multiplier circuit, just to start the tube. CFL's will run on DC, but they run cooler with a rippled current.

[triggernum5]

You'd polarize the bulb and it wouldn't work as well in an a/c socket if at all.. You may be able to get away with switching the polarity each time, but you'd still get Hg accumulations.. Also, fluorescent lights need to be current limited (ballasted) to stop them from sucking infinite power.. The efficent way to do that is with induction via a transformer, but transformers need A/C to function since current is a result of a changing magnetic field, not a static DC field.. If you do try it, wire it in series with a soldering iron or something (eg wire goes in one prong on the plug, through the soldering iron, and continues out the other prong before going to the light..) Better yet, do some research on ballasting first so you don't blow fuses and start electrical fires..

[Prometheus]

"polarize the tube"???? I'd like to hear about how to do this, since I have never heard of this before. As it has been understood since their creation, fluorescent tubes are simply bipolar capacitors that emit light at saturation.....I'm all ears on your theory on how to polarize a CL tube....

[Big Bwana]

I know if you run a tube on DC, It's not that it won't work again on AC or it will be hazardous, it will work fine and all that really happens when you run a tube on DC is you shift all the mercury to one end of the tube, causing it to blacken.. The fix for this is simple turn the tube around and the mercury will shift to the other end of the tube... (( The only true DC driven tube I've seen was in an old elevator and the power supply would alternate it's output every couple of hours )) other wise it was the same as a 4 foot 34 watt tube running on AC well ok it was just a wee bit shorter then a 34 watt 4 foot tube and it used 40 watts and cost about 20 times as much and it had a silicone shatter coating ))

[westfw]

The 5V CFL I mention uses an off-the-shelf CCFL inverter module (such as you find powering your laptop backlight.) While the CFL tube has filaments at each end for pre-heating, they're not absolutely necessary if you can generate higher start voltages, and not even all CFL circuits end up using the filaments for startup. (The inverter only runs about 3W, so regardless of what sized tube you have, you get about 3W worth of light out of it.)

[Prometheus]

The only purpose for the electrode heaters is to lower the breakdown current to start the tube. Once the tube is lit, less current is required to keep it lit. To generate that higher start voltage would necessitate you dropping that once the tube started, or risk an excess current running through it, frying the source due to a relative short-circuit. Some cheaper circuits use a start capacitor to spike the voltage to get the tube to start, but this is a weak and unreliable method.

[triggernum5]

Really? Heat lowers resistance? Thats rockin cool, I'm going to go get rich off that notion tomorrow.. Here I was thinking that heat increased resistance, and that the purpose of the filament heaters had to do with facilitating thermionic electron emmision at the cathode.. Google could have prevented that one..

[westfw]

Heated filaments in a CFL lower the overall tube resistance because:

• the heat vaporizes (and perhaps ionizing) more of the mercury.
• hot filaments emit electrons.

[Prometheus]

finally a more intelligent version of the truth....Keep in mind those elements are not active beyond starting as the main excitation has already commenced....

[triggernum5]

Ok, I digress, you aren't an idiot, but this is an internet hobby site, now atleast readers will understand that electron emmision ionizes the gas.. Ppl who aren't atleast halfass educated in this already are just going to be mislead.. Honestly it was the length of your posts that made me doubt you.. Seemed like over compensation.. When you make your point in 20 lines or less its much clearer..:)

[Prometheus]

Hey, stop being silly. If you understood simple fact, heat lowers the breakdown voltage of a gas to initiate electron flow. Before you go and post a half-arsed comment like that, be sure you know what you are talking about and stay out of a field you have no experience in. Heat increases resistance in a static conductor, but decreases resistance in a dynamic conductor, such as a gas. Before you prove yourself a moron, study high-voltage theory and especially ion-saturation principles of a reactive gas. In your ignorance, you proved me right at the same time. Take more time to rehearse your comments before you post them, if you even remotely understand what you are talking about. WTF do you think thermionic electron emission is caused by and principled on when it comes to excitation of a gas, Mr. Einstein? Perhaps you have a new theory on a cold vacuum tube? I suppose the vacuum tubes of a previous era had heaters just to keep the cabinet warm? Perhaps to light the cabinet to make a serviceman's work easier? Maybe just out of a compassion to give a cat something warm to sleep on? Maybe you should google "basic electronics" for your next search....Stay out of this discussion, your ignorance is not welcome.

[Big Bwana]

<> that was in the days before nocat thats why they where so warm

[JoelDude]

pwoned!