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Author Topic: Joule Thief  (Read 5818374 times)

Offline Farmhand

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Re: Joule Thief
« Reply #16575 on: July 24, 2014, 11:30:28 AM »
I ordered 50 pieces of adapter boards for SMD parts, up to 8 pin devices with two different sizes one side of the adapter pcb has
a small 8 pad mount and the other side has a slightly larger one, they should fit my needs I think.

With the 1400's parts pin 1 and pin 2 can be soldered together on the left side and the Lx and ground pin are "one pad apart" on the other side which makes soldering a bit easier.

The hookup is fairly simple + rail to coil to Lx pin, diode from Lx pin to + of output capacitor, gnd to circuit gnd, pin 1 and pin 2
together and connected to the output side of the diode. no contact pin 3 is isolated, it could be folded up out of the way maybe.

Also the enable pin 1 "CE" can be left floating as it has an internal pull up. Only pin 2 the output voltage monitor pin actually needs to be connected to the output side of the diode.

Sharp solder point, lots of magnification, thin solder and maybe some solder paste helped me a lot.

I quickly became a fan of surface mounting in general where structural strength is not needed.

.

Offline MarkE

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Re: Joule Thief
« Reply #16576 on: July 24, 2014, 01:36:29 PM »
For fairly low cost SMT soldering Hako has a bunch of product.  I like the OKI/Met-Cal gear better.  If you can spring for an MFR1110 and three or four tips you will have a nice set-up for casual work.  For more serious work, you want a preheater, a hot air gun and solder paste.

Dave45

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Re: Joule Thief
« Reply #16577 on: July 24, 2014, 03:52:14 PM »

Offline d3x0r

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Re: Joule Thief
« Reply #16578 on: July 24, 2014, 04:13:41 PM »

I'm really liking these NTE172A aka 2N5306 darlington with 7k HFE. (MPSA18 work about the same; tested somewhat success)


(ya I know, it's not really much like a joule thief anymore; I'm calling it a ka4ep torch.. I should probably just start its own thread; and so I did http://www.overunity.com/14794/ka4ep-torch-kacher-torch/ )


I'm waiting on this test to finish to see how long 2 series AAA batteries last... going on 26 hours now; down to 2.55V. 
Joule thieves were nice to start with, but they draw a lot of current for not much gain; though I did find a high inductance third winding as a pickup made lighting lots of LEDs easy... since no matter how many you have in series you still only need 20mA... voltage is cheap, it was getting current that was the issue...
( http://www.allaboutbatteries.com/Energy-tables.html *sigh* this says an alkaline AAA yas 1150 mAh; which is 76 hours or like 3 days :( ... or 1.41Wh, of which I've used 0.49 in 26 hours... so this 3Wh supercap should last for days... need to figure how to use more power with this )
10mA for 500nS at every 12us(83Khz)... 24% duty cycle.. 2.5mA across the load :/ that's not very good power usage at all. well.. I guess... it's 25x the voltage... so can't be too bad (the 500ns isn't constant it's just the width of the bellcurve generously)
-----------


The capacitor that's used kinda matters...
The load that's used kinda matters....


Wish my scope had an integral (sum under the curve) function... It looks to me that 3 of these are lower current than the lower left, even though the lower left peaks out lower... Need a slightly bigger 350V cap (40uF 400V foil wound cap is bad)
Ceramic caps of various voltages also have basically a constant current draw.


Was puzzled by the continuous current draw (lower left image in composite) for a while because the only place power is connected is on the one coil... so why should it be a constant draw... then I realized the cap has an ESR, which the battery apparently can't quite keep up with... actually it's probably more of an capacitive impedance issue... that it takes X power to charge the cap at Y voltage so it can only take so much current in at a time... so I experimented with caps, and only found this one that goes down to 0 current.
I had added CSR's in various places and finally found that I am only returning 2mA for a short time in an decreasing slope (2mA max, decreasing over the span of T2 in the second image).  And since I had a constant draw of 15mA that was basically nothing  (it does help though, and is more than 0).


(yellow trace in composite is in same location; green trace in composite is on the collector, and it's biased from the 2.55V, yellow resistor is 1Ohm so mV=mA.  Lower right image green is moved to top end of secondary)

---
Edit: also the lower right ended up missing the bounce-curve, but that's cause I had a scope probe connected where I did... adding a few hundred pF of capacitance to ground does the same effect... but reduces the output a lot... have to tinker with that some.
« Last Edit: July 24, 2014, 06:14:21 PM by d3x0r »

Offline MarkE

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Re: Joule Thief
« Reply #16579 on: July 24, 2014, 06:09:24 PM »
If your scope exports .csv data then you can use a spreadsheet program to derive almost anything that you think of calculating.

Offline d3x0r

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Re: Joule Thief
« Reply #16580 on: July 24, 2014, 06:15:06 PM »
That's a thought; have to change scopes around by could probably manage that.

Offline magpwr

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Re: Joule Thief
« Reply #16581 on: July 26, 2014, 08:09:32 AM »
hi everyone,

I have just uploaded a youtube video of my recent discovery-  Powerful toroidless joule thief
http://www.youtube.com/watch?v=QP8PkgT1T9o

This is the 4th version of my toroidless joule thief circuit as there are other types shown in my youtube channel :sanjev21 which is not using toroid and yet able to light led brightly.This is the final version.

Without the use of  any toroids would take the overall cost building a joule thief circuit to a new low.Here i am talking about avoid buying toroids which cost money unless you got some spares from salvage after which you still need to wind the coils.

The  Powerful toroidless joule thief  circuit can be assembled in less than 5minutes on a breadboard once you got the components ready.

The schematic is revealed in the video.

Component list
2222 transistor
4.7 kohms resistor
10nf capacitor
100uH x 2 inductor
Led

 

Offline TinselKoala

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Re: Joule Thief
« Reply #16582 on: July 26, 2014, 08:42:15 AM »
But... but.... Toroids are _magic_, aren't they?
 :P



(Just kidding, nice work!)

Offline Hoppy

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Re: Joule Thief
« Reply #16583 on: July 26, 2014, 10:17:36 AM »
hi everyone,

I have just uploaded a youtube video of my recent discovery-  Powerful toroidless joule thief
http://www.youtube.com/watch?v=QP8PkgT1T9o



That's like a Bedini without the wheel  ;)

Offline MarkE

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Re: Joule Thief
« Reply #16584 on: July 26, 2014, 12:14:50 PM »
hi everyone,

I have just uploaded a youtube video of my recent discovery-  Powerful toroidless joule thief
http://www.youtube.com/watch?v=QP8PkgT1T9o

This is the 4th version of my toroidless joule thief circuit as there are other types shown in my youtube channel :sanjev21 which is not using toroid and yet able to light led brightly.This is the final version.

Without the use of  any toroids would take the overall cost building a joule thief circuit to a new low.Here i am talking about avoid buying toroids which cost money unless you got some spares from salvage after which you still need to wind the coils.

The  Powerful toroidless joule thief  circuit can be assembled in less than 5minutes on a breadboard once you got the components ready.

The schematic is revealed in the video.

Component list
2222 transistor
4.7 kohms resistor
10nf capacitor
100uH x 2 inductor
Led
Here is the schematic, and an alternate variation that is more efficient.  The original circuit produces sine waves.  The alternate circuit is trapezoidal with fast edges.

Offline TinselKoala

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Re: Joule Thief
« Reply #16585 on: July 26, 2014, 12:46:56 PM »
Wow, a mosfet with a 1v max gate threshold voltage. That's pretty cool. I just wish it was big enough for me to see without magnifiers!

Offline magpwr

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Re: Joule Thief
« Reply #16586 on: July 26, 2014, 02:22:52 PM »
Here is the schematic, and an alternate variation that is more efficient.  The original circuit produces sine waves.  The alternate circuit is trapezoidal with fast edges.

hi MarkE,

That's the way man.

Research and development faster than a bullet train.

This is the way how i love to get things done.

To sit and rest and watch our bio-clock tick away is not the way.

-------------------------------
I was merely thinking earlier on in the day to connect to a 1n4148 diode to 22222 transistor collector and use a 1uf capacitor at diode output to act as a voltage doubler for my programmable pic12f675 chip which can run as low as 2volts.

I have attached a tiny video of my quick programmed pic12f675 doing 2 led flip-flop running of from 1 x AAA battery.

I'm sure the improved version of yours can power up even more components in a assembled circuit using 1 battery.Nice

Offline MarkE

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Re: Joule Thief
« Reply #16587 on: July 26, 2014, 03:07:13 PM »
hi MarkE,

That's the way man.

Research and development faster than a bullet train.

This is the way how i love to get things done.

To sit and rest and watch our bio-clock tick away is not the way.

-------------------------------
I was merely thinking earlier on in the day to connect to a 1n4148 diode to 22222 transistor collector and use a 1uf capacitor at diode output to act as a voltage doubler for my programmable pic12f675 chip which can run as low as 2volts.

I have attached a tiny video of my quick programmed pic12f675 doing 2 led flip-flop running of from 1 x AAA battery.

I'm sure the improved version of yours can power up even more components in a assembled circuit using 1 battery.Nice
If you want something really compact and efficient for that type of application then I recommend an NCP1400.  You can more or less name your output voltage:  2.5V, 3.0V, 3.3V etc.  SparkFun sells an NCP1402 board for $6.  The only downside to that is that if you have a very light load the voltage will float up on you.  That's a potential problem for A/D work, but may be fine for many applications.  You can buy the SparkFun board and remove the NCP1402 and replace it with an NCP1400.  The standby current on the NCP1400 is very low.  So you can use this for things that need to run on a battery for months at a time.

Offline magpwr

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Re: Joule Thief
« Reply #16588 on: July 26, 2014, 05:37:20 PM »
If you want something really compact and efficient for that type of application then I recommend an NCP1400.  You can more or less name your output voltage:  2.5V, 3.0V, 3.3V etc.  SparkFun sells an NCP1402 board for $6.  The only downside to that is that if you have a very light load the voltage will float up on you.  That's a potential problem for A/D work, but may be fine for many applications.  You can buy the SparkFun board and remove the NCP1402 and replace it with an NCP1400.  The standby current on the NCP1400 is very low.  So you can use this for things that need to run on a battery for months at a time.

hi MarkE,
This is a interesting component which you recommended.
I did spot a seller in China is selling 10 pieces which output 5volts at $3.22USD with free shipment.
http://www.ebay.com/itm/10PCS-NCP1402SN50T1G-ON-IC-REG-BOOST-5V-0-2A-5TSOP-NEW-R5-/291114101279?pt=LH_DefaultDomain_0&hash=item43c7c0aa1f
Taking cost of other supporting smd components it would be around $1 to diy.




Offline Pirate88179

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Re: Joule Thief
« Reply #16589 on: July 26, 2014, 07:25:09 PM »
I have not as of yet fired up the 1402's but, I think I like the specs better than the 1400's.  At least, for what i am attempting to do.

I can't believe the price (cheap) on those sparkfun 1402 breakout boards.  It does not really say but do the components shown actually come with the pc board?  Or, is it just a board?  When I get paid, I will order a few of them.  (Thanks Mark E.)

All I am trying to do is have a small circuit that lights several leds and will run a battery down to .3 volts.  According to what I think I have read on their site, the sparkfun boards as shipped will not do that.  But, as mark suggested, I can manipulate my components onto the board and that would be a great, cheap, and easy way of prototyping.

Farmhand:

Thank you for your explanation of the 1402 hook-up.  You just saved me hours of work over here and I appreciate that.

Bill