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Is there any use for the tiny transformers in compact florescent light bulbs? Answered

Can the tiny little transformers be of use in simple electronic experiments? Can they be used in place of a toroid in a Joule thief?


The answer to each of your three questions is: Yes, Yes, and Yes, respectively.

Moreover, I claim that the real "trick" to recycling the little transformers and inductors found in old CFLs, involves taking apart the little ferrite transformer cores and then putting new windings them.

Or maybe what I'm saying is that you have more freedom over the number of things you can build with old CFL transformer/inductor cores, if you're not constrained by the windings already on them.

However taking these transformers apart, without breaking the brittle ferrite core pieces, involves some dark, dark magic... sort of. You remember the line from Macbeth: " Double, double, toil and trouble, fire burn and cauldron bubble." It turns out that one method for taking apart these transformers is by literally immersing them in boiling water. It weakens the glue holding the two pieces of the ferrite core together.

Just so you know I'm not making this story up, I have seen talk of boiling transformer cores in the comments of an instructable, here:

Also I have myself tried subjecting to boiling water, transformers and inductors pulled from old CFLs, and had some success with this trick. Also some failures. I think it may depend a lot on what kind of glue each particular manufacturer uses for their transformers.

As an example, the pictures below show a custom inductor, made by putting new windings onto a core from an inductor pulled from an old CFL.

Regarding the trick of taking apart old CFLs without breaking the glass, mostly this involves being careful. See also:


There's a use for everything.

However, the problem with compact fluorescent bulbs is that if you break the bulb to get at the transformer, you're doing environmental damage in excess of the benefits. Compact fluorescents should be disposed of properly because they contain Mercury, which is a well known poison...

In the EU, unlike here in the US, I believe that recycling is mandated by WEEE. Sadly, The US government has not imposed such restrictions here yet. Thank goodness for our wonderful Wall street rulers.

I haven't had to break the actual "bulb" to take them apart - I just separate the two pieces of the base. Does this also release mercury?

no, not as long as you don't open the sealed tube. that's the critical difference. :-) Make sure to take the bulbs to a recycling location for proper disposal rather than throwing them in the garbage. In the USA, that would be HomeDepot. In the EU, it *seems likely that it would any hardware retailer that sells compact florescents. Not sure about other countries or locales.

You can use them to make high-voltage supplies, and as part of a tesla coil. Apparently.