Compact Florescent Light bulb (CLF) Breakdown

I was asked to post pictures of my process for getting circuit boards out of CFL bulbs on this thread: http://www.scrapmetalforum.com/scrap...ght-bulbs.html


It seems kind of odd for the "Scrap Spots" section so I thought I would post it here.

CFL bulbs are everywhere now and when they burn out it is because something goes wrong on a little circuit board inside of them. I was being a geeky engineer and decided to take one apart to see what was wrong. Since then I have taken all the ones I get apart, mostly for fun, and rescued what scrap I can out of them. Now I am always very careful and make sure not to damage the tube as it contains a small amount of gas containing mercury. These bulbs can be taken apart leaving only this tube as seen below.

Here is the basic bulb, This one is a small one so it was a bit harder to take apart.


The first step to to break off the metal screw in endcap. This is plated copper.
As you can see once the metal is off you can already see an aluminum can capacitor peaking through.


Once the end cap is off you can begin removing the plastic shell. Once you get practiced you can break the whole shell of at once with a large pair of pliers or channel locks and just crush the plastic. However, it is easy to take it off one piece at a time with a pair of diagonal cutters. It only take a few seconds to break it all away.







Now you can see the circuit board. This is the spot you have to be careful. Wires come up from underneath the board and connect it to the tube itself. This is the only time you are near the tube that many people are afraid of. You can see the wires from each side of the board connecting to two terminals on each side. Just a few snips and the board is free.





Now the circuit board is free! And the tube is intact. I know where I am from I can take the tubes to Home Depot or the local landfill for free recycling. Here is a picture of the remains of the bulb. You can see the two ends of the tube intact.



Here is the underside of the board. As you can see there are a number of rectifying diodes (the black boxes), a surface mounted monolithic capacitor, and some ruthenium surface mount resistors. I know both the monolithic capacitors and the ruthenium resistors have value in large numbers. If someone was saving them up each bulb would contribute a few.



Here is the top of the board. There is a small transformer, a number of capacitors, a few transistors, a copper wrapped ferrite torroid, and a few other components.




Here is the main take from the bulb. The small transformer, the black copper filled induction coil, three transistors (The square one was under the ferrite torroid) and the torroid itself with a bit of copper around it. I know the torroids can sell on fleebay in numbers.

On another note this component was on the board. I am not 100% sure what it is. Under the component the board said PTC. On the component it says DM25, has a blackened triangle on it, and a number 8 on it. Any input would be appreciated!

Thank you! That is an awesome demo. I'm looking forward to trying this.

Do you remove the copper from the torroid and then sell the torroids? Or are they only sold with the copper still on them?

People reuse them by winding wire around them. So you have to remove the copper. Its kind of a pain but it works.

First off...nice breakdown CMG, my hat off to you. Very nice an good explaining!

Now I took the time to check ebay as you said they sold there, an I'm seeing these suckers sell with the copper, but you say..remove the copper. Is there a reason for this other then to let the next person who gets it rewrap it? An why are the ones for sale being sold with the copper? Are they all new? When you post them do you mention them being used?

Just questions I have after looking at some folks selling them. 20, 40, 129 bucks..wth. Heh. I don't deal with ebay anymore, so I'm just really curious the allure an high bucks behind these things. It's enough to make me stop smashing them for copper, an finding another outlet for them, that doesn't require dealing with eBay.

Again..excellent post, an sorry for the silly questions, but you do have me curious now.

Edit: An thanks Jill for asking him to post the pics an details!~

Sirscrapalot - who knew?! - everyone at some point.

We need to add Torroid Bucket to the master list, wherever it is. With or without the Cu windings.

Originally Posted by Mechanic688

The green thingie is a capacitor. The 25 is probably the 25 volt rating.

But it is a tantalum capacitor?

Thanks for the info on the capacitor. My guess was a ceramic capacitor but I have normallu only seen the dish shape.

Originally Posted by Sirscrapalot

First off...nice breakdown CMG, my hat off to you. Very nice an good explaining!

Now I took the time to check ebay as you said they sold there, an I'm seeing these suckers sell with the copper, but you say..remove the copper. Is there a reason for this other then to let the next person who gets it rewrap it? An why are the ones for sale being sold with the copper? Are they all new? When you post them do you mention them being used?

Just questions I have after looking at some folks selling them. 20, 40, 129 bucks..wth. Heh. I don't deal with ebay anymore, so I'm just really curious the allure an high bucks behind these things. It's enough to make me stop smashing them for copper, an finding another outlet for them, that doesn't require dealing with eBay.

Again..excellent post, an sorry for the silly questions, but you do have me curious now.

Edit: An thanks Jill for asking him to post the pics an details!~

Sirscrapalot - who knew?! - everyone at some point.

I think only the ones with a lot of copper get sold with the copper on it. I know most of these get reused by people who do their own electronics. Lots that say used don't seem to go for quite as much as the new ones, but still sell for a lot more than the steel price! I know when I search for " ebay ferrite chokes" or "ebay ferrite torroids" in google I find many lots with no copper.

I am glad you found the post interesting. I know I sure found how much stuff was in one of those bulbs to be cool!

Originally Posted by jiffy117

PTC is a Positive Temperature Coefficient thermistor. Most likely shuts circuit off when it overheats. That's why these bulbs will work for short periods of time near end of life, when they overheat they "shut off". The symbol on the board is for a temperature device.

Thanks Jiffy! Now I know what all the components on that bulb were.

Sirscrapalot,

I collect the torroids and put them in with my other transformers and small electric motors that are too small to tear down and sell them at my yard for electric motor price, maybe your yard will do the same? Don't know for sure but it's worth a call to find out and then just throw em' in a bucket whole and cash em' in when you feel you have enough!! Hope that helps make things easier for you!! Happy scrappin'!!!

dsvtechie