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Author Topic: MEG-GA Joule Thief with very long runtime on just 1000 uF cap  (Read 19596 times)

Offline TinselKoala

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Re: MEG-GA Joule Thief with very long runtime on just 1000 uF cap
« Reply #15 on: May 21, 2014, 02:36:38 PM »
Ahhh Guys you do know what those Y and  X on the top don't you?

In case you are unsure they are put there in case the cap overheats it reduces the chance of a powerful explosion. Wether they have a Y or X or ~ is entirely up to the manufacturer. they do not in any way signify what type of cap it is.

I thought I'd add this in case there was some confusion.
There is no confusion on my part. I've blown up enough electrolytic caps to understand what those score-marks are for. They are there so that the case ruptures on the top and the guts come flying out vertically, rather than blowing up sideways and destroying other components too. When you do it right, the whole coiled up electrode strip unrolls like a party favor and you get a nice streamer up to the ceiling. Just don't be looking down at the cap when it pops!

Offline CuriousChris

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Re: MEG-GA Joule Thief with very long runtime on just 1000 uF cap
« Reply #16 on: May 21, 2014, 02:43:57 PM »
I know you know TK. but having blown up a few makes me worry about your electronic design ability. The idea is not to blow them up. ;)

I will confess to having inserted an electrolytic backwards but if I recall it was a fizzer :(

Offline Hoppy

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Re: MEG-GA Joule Thief with very long runtime on just 1000 uF cap
« Reply #17 on: May 21, 2014, 02:48:46 PM »

I will confess to having inserted an electrolytic backwards but if I recall it was a fizzer :(

Not enough voltage quickly enough Chris.  ;)

Offline Vortex1

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Re: MEG-GA Joule Thief with very long runtime on just 1000 uF cap
« Reply #18 on: May 21, 2014, 03:11:45 PM »
See my analysis, sims, builds and comments of such circuits here: http://www.overunityresearch.com/index.php?topic=2436.msg38725#msg38725

and here: http://www.overunity.com/14591/lasersaber-strikes-again-a-joule-thief-king/msg402952/#msg402952

Stefan's analysis at the beginning of this thread does not consider that you can run much less current in pulse mode, low duty cycle high peak current and get good brightness. He uses the steady state DC value to compare with pulse mode values for run time.