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Author Topic: Joule Thief  (Read 6276475 times)

Pirate88179

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Re: Jule Thief
« Reply #16500 on: March 04, 2014, 06:48:06 AM »
Pirate88179,

Do you have any idea what the current draw from
the 30 Volt battery might be?

If it is only a few milliAmperes it would be possible
to make a DC to DC Boost circuit to transform a
low two cell voltage to the needed 30 Volts with
pretty good regulation.

Do you remember the TI Scientific Calculators
from the '80s (TI-30) which were powered by either
a 9 Volt battery or the rechargeable 2-cell
NiCd boost replacement?

No, I don't know what the current draw is, but, it can't be too much.  The original battery inside was just a stack of oval hearing aid type batteries, like ten of them to get the 30 volts.  I solved this by using 3 nine volt batteries in series as I saw them do on an old radio restoration site.  (Some old radios used these batteries also)

 I don't recall those calculators but, if I saw one, I would bet it would ring a bell.  Your idea is a good one but the 9 volt batteries in series (outputting 28+ volts) works fine, at least in this application.

Bill

crowclaw

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Re: Jule Thief
« Reply #16501 on: March 04, 2014, 11:38:35 PM »
No, I don't know what the current draw is, but, it can't be too much.  The original battery inside was just a stack of oval hearing aid type batteries, like ten of them to get the 30 volts.  I solved this by using 3 nine volt batteries in series as I saw them do on an old radio restoration site.  (Some old radios used these batteries also)

 I don't recall those calculators but, if I saw one, I would bet it would ring a bell.  Your idea is a good one but the 9 volt batteries in series (outputting 28+ volts) works fine, at least in this application.

Bill
There you go Bill, yet another project for the JT circuit maybe for you!! Wind a small coil rectified DC output with cap, voltage divider to achieve target voltage. Clamp the voltage with a zener diode, etc... job done.
Worth a try maybe when you've got five.

Jeg

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Re: Jule Thief
« Reply #16502 on: April 14, 2014, 03:08:51 PM »
Hi guys

Nice thread but huge to search for what i need.  ???
I'd like to ask if anybody has a JT circuit driving an ignition coil if it is possible from 1.5V Even higher supply voltage is accepted. It's time to play with this small gadget!!! :)

Thanks
Jeg

crowclaw

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Re: Jule Thief
« Reply #16503 on: April 14, 2014, 08:38:20 PM »
Hi Jeg, just give it a try... the only problem I can see if you need to reverse the primary windings if it doesn't self oscillate!  You only have three connections on these coils, the primary and secondaries are common connections. Also beware of the high secondary voltages while experimenting. Otherwise drive it with a 555 timer IC, also these coils use an iron core so frequencies are much lower.

Pirate88179

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Re: Jule Thief
« Reply #16504 on: May 20, 2014, 02:45:06 AM »
I took apart another garden solar light and found this board.  As you can see (hopefully) it only has an inductor on one side of the board and that black blob covering the "mystery chip" on the reverse.  I removed it from the solar cell and the photo diode and tested the amp draw while lighting the straw hat LED very brightly.  It was only drawing 8 mA's while being powered by my power supply at 1.2 volts.  (I used a meter in series and not the display on my supply)

While researching this online I found a few guys that have this type of board with a chip not covered by the epoxy and they said it had 4 leads on it and no markings.  Another fellow said that the chip does the switching and the resistance as well.  This will light an LED brightly down to .5 volts and I want to know what it is so I can make my own boards and vary the resistance to control the lighting and mA draw.

Does anyone here know anything about this mystery chip and what it might be?  I have not put it on the scope yet but, the chip and the inductor and the built in resistor work as a JT in a very small and compact package. 

Any help here would be greatly appreciated.

Thanks,

Bill

PS  Every board I have like this labels that inductor as R1 so, until someone on here pointed out that it was indeed an inductor, I always thought it was a resistor.  I am always learning something from you guys.

TinselKoala

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Re: Jule Thief
« Reply #16505 on: May 20, 2014, 03:08:13 AM »
I dunno about the specific black blobs but I do know about two, four-terminal devices that are used in garden lights.



Pirate88179

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Re: Jule Thief
« Reply #16506 on: May 20, 2014, 03:17:17 AM »
TK:

Thanks a lot.  I appreciate the reply. Can we get these chips on the market anywhere or are they just a custom, in house item?  I didn't see any resistors in those circuit diagrams so I am guessing they are just like mine with the resistance "built in" to the chip somewhere.

Some of my earlier lights that I took apart (which looked identical to the one I took apart for the photos) had an external resistor on the board.  None of my boards have a schottky diode though.  I realize that there are many variants of this type of circuit.

I am just impressed as this is the most simple circuit I have ever seen that is an actual JT and it works very well.  If I could find some similar chips maybe we can make it better by experimenting with the inductors?

Bill

***EDIT***   I just found this: http://www.flytron.com/electronic-parts/240-ana608-solar-charge-and-led-controller.html

The ANA608 is available.  I will try to order some in the next few weeks.  Thanks again.

goku_092966

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Re: Jule Thief
« Reply #16507 on: May 30, 2014, 07:02:47 AM »
or you could try QX5252

from simple JT circuit on my night lights to this cheap solar garden light circuits...

credit goes to MrFreddiew1 who posted improvement regarding this circuit on Youtube.


Farmhand

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Re: Jule Thief
« Reply #16508 on: June 01, 2014, 09:19:11 AM »
Anyone got any info on a garden light IC 52521H with 1008 under it, 4 pins ?
I think I can read the board traces so I'll try to make a drawing.

..

Pirate88179

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Re: Jule Thief
« Reply #16509 on: June 01, 2014, 01:58:09 PM »
http://www.led-ics.com/pddetaildate/product/detail/20110321_10775860_52521H.html

I found this site and schematic.  You might be able to translate this page.  This schematic is similar to the ones TK posted elsewhere.  It appears this chip only works down to .9v.  Some of the other chips we have looked at go down to .6 which to me, is more useful.

Bill

Pirate88179

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Re: Jule Thief
« Reply #16510 on: June 01, 2014, 02:35:53 PM »
This is the smallest JT I have made to date.  I cheated and used a modified version of the garden light circuit board.  You can see another little board in the photos.  These are the ones with the gray blob over the chip.  All of the chips I have looked at would not fit under that blob so possibly it is an smd version?

This is a very bright little light and will light up down to .6 volts.  It draws less than 8 mA's when fully illuminated.

The case for the light is made from a 35mm film container lid and the base is made from a cut down Airborne (anti-cold herbal remedy) container.  It is the smallest package I could readily make but, there is a lot of room inside so it could be place in an even smaller package.

Bill

Pirate88179

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Re: Jule Thief
« Reply #16511 on: June 01, 2014, 04:18:25 PM »
https://www.youtube.com/watch?v=D6XVcqOs-Cg

Here is a short video of my Micro Joule Thief Light.

Bill

Farmhand

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Re: Jule Thief
« Reply #16512 on: June 01, 2014, 05:22:56 PM »
Cool stuff, your right the 52521H IC isn't much use for extended run times or for what I want
which is a more efficient circuit to run from a galvanic battery.

The setup in the picture below gives only 0.5 volts under load with about 1 to 2 mA, but I adjusted
the base resistance so that it runs the JT in burst mode powering two 5 mm LED's, meaning it
oscillates at 60 kHz until the voltage drops enough to pause the oscillations very briefly, that makes
the LED's brighter but flashing, another cell or a bit more current and it would run continuous.

It can run at 0.38 volts and more current. The cell has galvanized steel and
carbon arc gouging electrodes (copper coated with an inch of exposed carbon in the ground).


Pirate88179

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Re: Jule Thief
« Reply #16513 on: June 01, 2014, 05:34:28 PM »
Cool stuff, your right the 52521H IC isn't much use for extended run times or for what I want
which is a more efficient circuit to run from a galvanic battery.

The setup in the picture below gives only 0.5 volts under load with about 1 to 2 mA, but I adjusted
the base resistance so that it runs the JT in burst mode powering two 5 mm LED's, meaning it
oscillates at 60 kHz until the voltage drops enough to pause the oscillations very briefly, that makes the LED's brighter but flashing another cell or a bit more current and it would run continuous.

It can run at 0.38 volts and more current. The cell has galvanized steel and
carbon arc gouging electrodes (copper coated with an inch of exposed carbon in the ground).

Nice set-up.  Try using magnesium for the - electrodes and you should be able to get about 2.00 volts out of it.  That's about what I get, not counting those high spikes which will charge my 2.7 volt supercap fully.  I have a video on youtube running 200 leds off of my set-up and, I can also run a Bedini motor from it.  Get the largest block of magnesium you can and also, I would strip the copper off of the carbon rods as well.  Place the carbon rods on the north/south meridian to the north, and the magnesium to the south on the same line.  Not magnetic north/south, although, depending upon where you are these can be close.

I also have a cool video showing really high spikes all over the place on my scope.  It is these spikes that I assume are charging up my supercap (650 F) to 2.7 volts when I can only measure about 2 volts with my DMM.  I have been running this system for a long time now...well, actually right now it is not hooked up but maybe I should revisit this and explore it further?

Bill

TinselKoala

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Re: Jule Thief
« Reply #16514 on: June 01, 2014, 09:16:21 PM »
 8)