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Author Topic: Joule Thief  (Read 5815835 times)

Offline MileHigh

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Re: Joule Thief
« Reply #16890 on: February 21, 2016, 07:23:38 PM »
Yes I saw the spikes and it's highly likely that they are coming from all sorts of possible external sources, and not the corroding magnesium.

Offline Pirate88179

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Re: Joule Thief
« Reply #16891 on: February 21, 2016, 08:09:44 PM »
Yes I saw the spikes and it's highly likely that they are coming from all sorts of possible external sources, and not the corroding magnesium.

Well, I still like that I can light up all that I have been able to light up for free.  There was no 60 Hz component that I could detect but, I guess it does not really matter where the energy is coming from as long as it is usable right?

Also, my magnesium block still appears to be alive and well after about 5 years...although, to be fair, I have not run lights all the time from it...usually just around Christmas and special occasions.  I am sure that it will give out one day.  The carbon rods are just fine, as would be expected.

Bill

Offline MileHigh

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Re: Joule Thief
« Reply #16892 on: February 21, 2016, 08:27:48 PM »
If you read Revolution Green a company has what resembles an LED-based camping-style lantern that uses a magnesium cylinder and salt water to power the LEDs.  You get something like 150 hours (if I remember) from the cylinder.

Offline Pirate88179

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Re: Joule Thief
« Reply #16893 on: February 21, 2016, 08:43:55 PM »
Yes, I remember reading about that.  I believe Mark D. also posted a link to that story over here somewhere.

Bill

Offline Pirate88179

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Re: Joule Thief
« Reply #16894 on: March 01, 2016, 08:40:02 PM »
I still want to know why, when I "tuned" my simple JT circuits using a vr on the base that I could go past the sweet spot and would have to back up?


In other words, if I were just lowering the resistance, then the led would get brighter the lower I went...right?  So, why would the led get brighter and brighter and then start to get dimmer and dimmer and you had to tune back to hit the sweet spot?


This is going back about 8 years but I believe I replaced the 1k base resistor with a 5k vr.  You could tune it to get the best lighting and then, measure the vr and replace with that value resistor which is what I used to do.  But then, as has been discussed, the circuit would drift out of tune as the battery voltage lowered so I ended up just leaving the vrs in place most of the time.


Bill

Offline SeaMonkey

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Re: Joule Thief
« Reply #16895 on: March 01, 2016, 09:53:56 PM »
Excellent question Pirate.  It all has to do with the Current Gain
of the transistor and the region of saturation.

As base drive current is increased by decreasing the resistance
of the base feed resistor the transistor becomes more efficient
as a switching device as it approaches saturation.

Continuing to decrease the resistance will reach a point where
the base drive pulse amplitude is sufficient to drive the transistor
into saturation efficiently without excessive losses.

Reducing the resistance even further beyond that point will cause
the base drive pulse amplitude to increase base current even more
but with excessive losses.  The increased base drive is counter
productive as it is more than is needed to achieve saturation and
represents wasted power.  As a consequence the output of the
circuit (LED brilliance) will decrease indicating excessive power loss
and reduced efficiency.

The "sweet spot" is where the base drive amplitude is just sufficient
to put the transistor into saturation for minimum losses.

Offline Pirate88179

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Re: Joule Thief
« Reply #16896 on: March 02, 2016, 01:28:56 AM »
Excellent question Pirate.  It all has to do with the Current Gain
of the transistor and the region of saturation.

As base drive current is increased by decreasing the resistance
of the base feed resistor the transistor becomes more efficient
as a switching device as it approaches saturation.

Continuing to decrease the resistance will reach a point where
the base drive pulse amplitude is sufficient to drive the transistor
into saturation efficiently without excessive losses.

Reducing the resistance even further beyond that point will cause
the base drive pulse amplitude to increase base current even more
but with excessive losses.  The increased base drive is counter
productive as it is more than is needed to achieve saturation and
represents wasted power.  As a consequence the output of the
circuit (LED brilliance) will decrease indicating excessive power loss
and reduced efficiency.

The "sweet spot" is where the base drive amplitude is just sufficient
to put the transistor into saturation for minimum losses.

SeaMonkey:

Thank you very much for your detailed answer.  That makes a lot of sense to me.

Bill

Offline geovat

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Re: Jule Thief
« Reply #16897 on: October 27, 2020, 05:01:36 AM »
I have my universal printed circuit board for the AMP-2 soldered now.
Next step will be connecting a antenna and ground and
start measuring the output.

GL.

What about this?   ;)
https://earthenergy6.webnode.ro/_files/200000030-3b4de3b4e1/FREE-ENERGY-SCHEMATICS-3.PNG
-
https://www.youtube.com/watch?v=vGvKjxS5RRw

More infos:
https://earthenergy6.webnode.ro/low-currents-generator/


Offline erfandl

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Re: Joule Thief
« Reply #16898 on: July 03, 2021, 08:11:25 PM »
LS gadget mod self charge finally replicated and I'm happy :)

Start voltage: 2.613, After a week it is still at 2.613 volts.




Offline crowclaw

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Re: Joule Thief
« Reply #16899 on: July 03, 2021, 09:46:00 PM »
Hi Erfandl, this thread was started many years ago and it's been years since I last posted here.  As a point of interest, the schematic (post 16897) has an error relating to the output polarity markings for anybody replicating it.
It will be interesting to see how long your circuit will continue to uphold the charge, keep posting your progress and results. Regards Crowclaw 

Offline electricme

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Re: Joule Thief
« Reply #16900 on: July 03, 2021, 11:33:48 PM »
Hi Erfandl
Great looking JT, well done, try and let it keep going until the battery gives out which should be a long long time if they are fully charged.
One day I will get back into this thread again.


Keep up the good work.


Regards to all the old JT mates from a decade ago. electricme




Offline crowclaw

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Re: Joule Thief
« Reply #16901 on: July 04, 2021, 03:41:25 PM »
Hi, same here, I'm still around :)

Offline erfandl

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Re: Joule Thief
« Reply #16902 on: August 05, 2021, 11:54:35 AM »
Hi Erfandl
Great looking JT, well done, try and let it keep going until the battery gives out which should be a long long time if they are fully charged.
One day I will get back into this thread again.


Keep up the good work.


Regards to all the old JT mates from a decade ago. electricme
Hi electricme, crowclaw .sorry for late.
I removed the LED from the circuit and the results were slightly different:
I connected to the circuit a battery that had rested for 10 days and its voltage was 1.452. After 5 hours, the battery voltage increased to 1.458. But the voltage did not exceed 1.458 even after 1 day and was fixed at the same voltage. the coil still ringing  :)

Offline crowclaw

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Re: Joule Thief
« Reply #16903 on: August 05, 2021, 01:45:32 PM »
Thanks for keeping us posted, good work. Crow Claw

Offline norman6538

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Re: Joule Thief
« Reply #16904 on: August 05, 2021, 03:56:07 PM »
So does this mean the LED has been lit for a week and the Batt V has not gone down?
If so quite impressive.

How many free watts would that be?
I'm wondering what the antenna does in this circuit. I think that is new from my memory.
With the antenna this circuit is looking more like the Morray/Bruce Perreault work.

Which diode is the LED? 



Thanks

Norman