Joule Thief

[xee2]

if the current get higher then what the diode(s) alone can disipate,

If the current gets higher than what the diode(s) alone can disipate, then that is a very amazing EB.

[jeanna]

@Bill,
I was reminded today about the sometimes wild fluctuations in an EB.

Today I put the dmm on it and it started at0.024v and continued to rise to 0.101v and when I returned from looking at the scope elsewhere, the voltage was down again to 0.043v

I am pretty sure your cap in this instance would be holding 0.101v because it would have instantly raised its voltage to the high number and without something being there to remove the voltage, that voltage would still be there as it accumulates more amps over time.

The funny thing as I remember is that if there is a load it will pull more, but even without that element, I think this explains that your ground will peak to 2.5v so briefly that the dmm cannot see it, but the cap never lies.

I had this happen with a MK1.
The highest reading I could get on even the scope was well below the amount a fuji cap could collect.

But the cap is not capable of getting any higher than the highest voltage going across the leads.

Someone please correct this if I am wrong.

for what this is worth,

jeanna

[gadgetmall]

yes.


@Pirate88179
a cap, at 2.7volts, have 1755 coulomb or 1755 amps of energy in it.

1 ampere = 1 coulomb/second = 1 watt/volt

but note that as you drain the cap, the voltage will go lower.

about caps over voltage, AbbaRue is right.
caps can be over charged.
if the source voltage is higher then the cap's rating.
it will blow up if allowed to over charge.
i was assuming that the voltage of your EB was lower then the rating of your ultracap.



i am just a human, i do make mistake sometimes and i am the first to be sorry of that mistake.
that mistake costed me a few transistors.
i was having 107 times more amps in my cap then what i was thinking it had...

at 2.7volts 650F, the cap has 1755 amps in it, if it is discharged in 1 second.

but if you knew it, why did you not rectified me ?

i will stand corrected and admit i was wrong by anyone that can prove me wrong with a formula as an example or detail(s) of what i might have fergot.

the last thing i want is to spread is disinfos.

Hi NOp / Actually it was me that said a cap could over charge not abbarue . abbarue said QUOTE :AbbaRue

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Re: Jule Thief
« Reply #6739 on: June 02, 2009, 07:45:51 PM »

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@Pirate88179
You don't need to worry about shock danger when working with low
voltages like 2 volts.  I doesn't matter how many amps you have.
You could stick your tongue across that super cap when it is fully charged
and you would just feel a tingle on your tongue.
Even 12 volts is safe to handle.  You can touch the 2 terminals of a 12 volt
battery with your fingers without feeling anything as long as your
fingers aren't wet.
. He is DEAD Wrong . and second Dude , I didn't know I was Just passing what you said as you had already had a conversation about it before with someone else  way back and and i thought it was fact being you Correct everyone like a Physics teacher and an EE .Yes i know you are Human and make mistakes and spread disinformation with no i'll intent . It cool and now we both know .  . 

[nievesoliveras]

@all

I made the original self charger to work again using a circuit I had called YES Gate / NOT Gate.

Maybe one of those people with big capacitors want to give it a try starting with a charged capacitor, to see if it keeps the capacitor charged.

If anyone wants to verify the self charger, this is the repaired version.

Jesus

[electricme]

@ALL
Supercap warning,
Time for another cartoon folks

Artic_Knight:
There is a stern warning on the caps that if the polarity is not correct, it can explode with great force and cause damage or injury.  So, I was very careful in this.

These supercaps are really cool.

Bill

During my electrical apprenticeship there was a tradesman out in the back shed, working on an airconditioner. We heard a loud explosion, next we saw he and inside the shed was covered in silver paper, he was blinded by the flash, deafened by the boom, shaking like a leaf.
They are dangerous, so don't reverse the polarity.
Always check if the cap is leaking or has a bulging top

jim