Today's workshop disaster (minor) story

Thread Starter

Treeman

Joined May 22, 2014
157
So there it was staring me in the face- I'd been looking for a ferrite toroid to make a joule thief for some time. The old Samsung came right in the end. How did I not spot it before?
Joyously unwrapping the mains lead from it ; I was , like a magpie dazzled by something else on the board. Moving in I stubbed my finger with toroid on the bench and it promptly fell to the concrete floor.
I remembered reading that ferrite was fragile just this morning.....


Boo Hoo
 

DickCappels

Joined Aug 21, 2008
6,655
You don't need a toroid core.



Fusty nail



A piece of wood


This is a closet lamp effectively using an air core

Really, you can use almost anything or nothing as a core.

A good place to find ferrite cores in in compact florescent lamps -be careful not to break the glass and get cut and/or let the mercury out.

 

takao21203

Joined Apr 28, 2012
3,695
why the same pictures keep repeating over years?
These above are particulary bad even tough the circuits can light up single LEDs.

You should buy ferrites + inductors which work well means you only need small amount of turns, can light up more LEDs.

I used a Panasonic 10mH choke.

Not sure if that works with a nail I doubt it.
 

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Thread Starter

Treeman

Joined May 22, 2014
157
I tried a 10mm bolt last night with no luck - even after rechoosing the steel one from the Ali one I grabbed - skill. I like all these ideas, Dicks for ingenuity and scrap revaluation and takao because edfficiency is always king in the end.
I am adding more turns to the bolt as we 'speak'.

Thanks.
 

ian field

Joined Oct 27, 2012
6,539
You don't need a toroid core.


A good place to find ferrite cores in in compact florescent lamps -be careful not to break the glass and get cut and/or let the mercury out.

Been looking for a use for those "E-E" ferrite ballasts from CFLs - all the ones I've salvaged so far, had no room for any more turns.

Some CFLs have a diac in the startup circuit - you can get up to all kinds of mischief with them.

Once you get the joule-thief going, wind a big secondary and add a diode/reservoir electrolytic. Put a DB3 diac in series with a bank of parallel LEDs and stick that combination across the electrolytic - every time it charges to about 32V, it dumps upto 2A into the bank of LEDs.
 
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