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Author Topic: Lasersaber strikes again. A joule thief king ?  (Read 201937 times)

Offline a.king21

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #75 on: May 14, 2014, 12:17:43 AM »
TinselK, have you turned the mains off to ensure you're not picking up stray rf?

Free Energy | searching for free energy and discussing free energy


Offline MileHigh

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #76 on: May 14, 2014, 01:29:02 AM »
TK and All:

Have a look at the LM3909:

https://www.youtube.com/watch?v=87xMbWM8qz0

Just about everything said in that clip was my experience also.  I built my first LM3909 circuit in 1977.

MileHigh


Offline Pirate88179

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #77 on: May 14, 2014, 02:28:39 AM »
TK and All:

Have a look at the LM3909:

https://www.youtube.com/watch?v=87xMbWM8qz0

Just about everything said in that clip was my experience also.  I built my first LM3909 circuit in 1977.

MileHigh

That was a cool video.  Hard to believe it was that long ago.  I must be getting really old... 

Someone, somewhere on here told me of a new 555 that will run down to like .35 volts and uses very little power.  I can't find the thread from that post and hence, can not find the part.  It is supposed to be what is under the gray blob of epoxy on those led garden lights.  (I have some that I have tried to dig under that blob with no success yet)

 Do you have any idea what those chips might be?  Years ago you suggested using a 555 for the JT circuits and the only reason I didn't want to do that was they required more voltage than I was working with at the time.  Whatever these "new" 555 chips might be would change all of that.  As you know, those garden lights only start with 1.2 volts max after charging, and will run an led all night so, whatever that chip might be is way more efficient than any of my 555's I have here.

Thanks,

Bill

Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #78 on: May 14, 2014, 08:24:07 AM »
Have a look at the LM3909:
https://www.youtube.com/watch?v=87xMbWM8qz0

If you look at the data sheet of the LM3909 (is attached) you find on the first page:

Low current drain, averages under 0.5 mA during battery life.

The 0.5 mA power drain is about what I achieved with my circuit, see:
http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402222/#msg402222

The road to very low power draw:

- 100 Hz flash rate
- very short pulse
- low LED current (rather dim LED)

In my circuit the pulse is already very short but happens at about 5 KHz, the LED current is already low (dim LED). By having more windings (thinner wire) on my core the frequency can be lowered. How can the pulse be made shorter?

Remarks:

The LM3909 uses a peak LED current of 45 mA at 1 Hz (slow) or 1 KHz (fast) to have a bright flash.

The supply current of a NE555 is between 5 and 15 mA (5V to 15V), therefore it is of little help.

LaserSaber's special core and the 2N1304 transistor seem to operate at less than 10 µA (at about 12 V) on average.

Greetings, Conrad


Offline TinselKoala

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #79 on: May 14, 2014, 03:10:15 PM »
TinselK, have you turned the mains off to ensure you're not picking up stray rf?
No, I haven't, not for that particular device. This circuit is tuned to match the wireless transmitter's operating frequency which is quite a bit higher than our mains frequency. I do have others that will glow from the house mains emanations though.

Free Energy | searching for free energy and discussing free energy

Re: Lasesaber strikes again. A joule thief king ?
« Reply #79 on: May 14, 2014, 03:10:15 PM »
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Offline TinselKoala

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #80 on: May 14, 2014, 03:11:37 PM »
TK and All:

Have a look at the LM3909:

https://www.youtube.com/watch?v=87xMbWM8qz0

Just about everything said in that clip was my experience also.  I built my first LM3909 circuit in 1977.

MileHigh

Heh... think of what 99 cents would buy you in 1977... it's equivalent to about 5 dollars today!

Offline TinselKoala

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #81 on: May 14, 2014, 03:15:38 PM »
If you look at the data sheet of the LM3909 (is attached) you find on the first page:

Low current drain, averages under 0.5 mA during battery life.

The 0.5 mA power drain is about what I achieved with my circuit, see:
http://www.overunity.com/14591/lasesaber-strikes-again-a-joule-thief-king/msg402222/#msg402222

The road to very low power draw:

- 100 Hz flash rate
- very short pulse
- low LED current (rather dim LED)

In my circuit the pulse is already very short but happens at about 5 KHz, the LED current is already low (dim LED). By having more windings (thinner wire) on my core the frequency can be lowered. How can the pulse be made shorter?

Remarks:

The LM3909 uses a peak LED current of 45 mA at 1 Hz (slow) or 1 KHz (fast) to have a bright flash.

The supply current of a NE555 is between 5 and 15 mA (5V to 15V), therefore it is of little help.

LaserSaber's special core and the 2N1304 transistor seem to operate at less than 10 µA (at about 12 V) on average.

Greetings, Conrad

You can choose your power draw based on how bright you want your LEDs to be. If all you are concerned about is getting a glimmer of light, where you can see the little wires inside the LED.... then you can make your power draw very low, as we have seen, and if you don't use dissipative elements like resistors in your circuit you can make this tiny glimmer for a long time.

But what if you want enough light to actually see something, or read a label? Show me a JT that operates on less than 10 uA at _one volt_ input not 12 ... and is bright enough to read by ... please.

Free Energy | searching for free energy and discussing free energy

Re: Lasesaber strikes again. A joule thief king ?
« Reply #81 on: May 14, 2014, 03:15:38 PM »
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Offline lasersaber

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #82 on: May 14, 2014, 04:17:18 PM »

Quote
But what if you want enough light to actually see something, or read a label? Show me a JT that operates on less than 10 uA at _one volt_ input not 12 ... and is bright enough to read by ... please.


I am working on it.  It might be possible.  When I reach best possible performance I plan one making a super low current draw flashlight.


I did have significant progress since the Mother's Day circuit: http://youtu.be/6B79UJGoNJE  That circuit was using around 25uA.  Using a different germanium transistor and a bridge rectifier I was able to reduce the current to 15uA while maintaining, if not increasing, the brightness.  I have since burned out all my germanium transistors doing crazy tests.  I have never had one burn out under normal operation.  It usually happens while trying to recapture energy with a rectifier.


Here is a link to my latest video showing DC vs SJR testing: http://youtu.be/5EkXNRWAi1Y

Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #83 on: May 14, 2014, 04:25:35 PM »
You can choose your power draw based on how bright you want your LEDs to be. If all you are concerned about is getting a glimmer of light, where you can see the little wires inside the LED.... then you can make your power draw very low, as we have seen, and if you don't use dissipative elements like resistors in your circuit you can make this tiny glimmer for a long time.

But what if you want enough light to actually see something, or read a label? Show me a JT that operates on less than 10 uA at _one volt_ input not 12 ... and is bright enough to read by ... please.

The whole exercise (trying to light a LED with an electrolytic capacitor for many minutes) is of course a little silly. There is the hope of finding some "energy gain" in a high impedance core used in a certain way. This hope is of course also silly, but why not?

I think that Steorn tried that and failed and many others looked for some "energy gain" in the brake down of magnetism in a core. The idea is that one gets more electricity back when the magnetic field brakes down than one used when magnetising the core. But nobody ever could show that conclusively.

Do not look for any use, look for the fun in trying something strange! And do not take it too seriously.

About my experiments: I could not put a copper strip between core and coil former because the core has to be insulated (otherwise it would shorten the copper strip). Insulation plus copper strip are too thick. It has to wait till I get the 2N1304 because I want to try it with the coil without copper strips first. I have the suspicion that the copper strips are of little help.

Greetings, Conrad

Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #84 on: May 14, 2014, 04:41:04 PM »

I am working on it.  It might be possible.  When I reach best possible performance I plan one making a super low current draw flashlight.


@Lasersaber: did you ever use a coil without the copper strips in this circuit (with your special pot core)?

I saw that my electrolytic capacitors (one 4700 µF and 50 V, the other 4700 µF and 25 V) have a leakage current of about 30 µA. This means that I can never go below a 30 µA power draw when using these caps.

Greetings, Conrad

Free Energy | searching for free energy and discussing free energy

Re: Lasesaber strikes again. A joule thief king ?
« Reply #84 on: May 14, 2014, 04:41:04 PM »
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Offline xee2

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #85 on: May 15, 2014, 04:32:15 AM »

I saw that my electrolytic capacitors (one 4700 µF and 50 V, the other 4700 µF and 25 V) have a leakage current of about 30 µA. This means that I can never go below a 30 µA power draw when using these caps.



The 10,000 uF 25 volt electrolytic capacitors I used were definitely below 1 uA leakage, so maybe yours are not as bad as you think.
This a Joule thief using less than 2uA that runs for over 1.5 hours from a charge of 1.36 volts:
http://www.youtube.com/watch?v=8T9HQkDnIuU
It could not do that if the capacitor leakage was over 1 uA.

Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #86 on: May 15, 2014, 12:13:44 PM »
The 10,000 uF 25 volt electrolytic capacitors I used were definitely below 1 uA leakage, so maybe yours are not as bad as you think.
This a Joule thief using less than 2uA that runs for over 1.5 hours from a charge of 1.36 volts:
http://www.youtube.com/watch?v=8T9HQkDnIuU
It could not do that if the capacitor leakage was over 1 uA.

@xee2:

Thank you for posting your interesting circuit. I saw it in 2011 and even filed it in my circuit collection, but I have completely forgotten.

Like always, everything has been done before.

Greetings, Conrad


Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #87 on: May 15, 2014, 06:50:08 PM »
Astable multivibrator with a MAX931 comparator drives a red LED with 12 µA at 2.5 Volt (LED rather dim):

The circuit without a LED needs just about 5 µA at 2.5 V to 3 V to create a nice square wave signal. Frequency and duty cycle can be adjusted by two resistors. The 1 M resistor defines frequency and the 5 K resistor duty cycle.

I have chosen a frequency of about 120 Hz and a duty cycle of only about 1 %. With this narrow square wave from the comparator output a red LED is driven through a 1 K resistor to reach this low power draw.

By removing the 5 K resistor between diode and 10 nF capacitor the duty cycle can be changed to 50%. The LED becomes of course brighter and power draw goes up ten fold. (See the measurement stated on the circuit diagram).

I found a similar circuit on the internet http://www.discovercircuits.com/DJ-Circuits/1HZOSC1.htm, but I prefer the MAX931 because it has a bigger footprint which makes it easier to handle than this awfully small components like the LMC7215.

This is not useful as a LED driver (a Joule Thief would drive a LED with 1 Volt instead of 2.5 V) but might be a useful circuit to generate a square wave with very low power draw (5 µA at 2.5 Volt). With this very "cheap" square wave one can then switch a MOSFET which in turn drives the primary of a transformer to light a 220 V LED lamp. One can select an efficient frequency and duty cycle. I will try that tomorrow.

Greetings, Conrad

P.S.: Some might want to learn more about multivibrators based on an OpAmp:

 http://www.expertsmind.com/topic/operational-amplifiers-and-their-applications/astable-multivibrator-using-op-amp-comparator-918025.aspx

 http://www.daenotes.com/electronics/digital-electronics/astable-multivibrators-working-construction-types
 
 http://www.electronics-tutorials.ws/opamp/op-amp-multivibrator.html
 

 

Offline Vortex1

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #88 on: May 15, 2014, 07:16:58 PM »
Thank you Conrad, nice to see power input, output and duty cycle data.

R-C relaxation oscillator circuits such as the Max930 are necessarily dissipative i.e a part of the energy used to charge the capacitor through the resistor is never recovered. 1 Meg and 10 nF RC is not much dissipation. You also have the wasted bias current of the comparator to deal with.

A different approach is to charge an inductor directly from a voltage source, then dump the inductor energy into the LED. The inductor will act as a near pure current source, so LED threshold voltage is easily exceeded, and current to the LED is limited only by the winding resistance resulting in a high peak current for a very short time. LED's appear very bright to the eye, although average current is low.

Most blocking oscillators such as the JT circuit attempt to do this, however the core must begin to saturate for the circuit to switch off and this dissipates power in the resistance of the winding.

A better way is to switch off before saturation and control the cycle by cycle charge into the inductor.

The Lasersaber circuit is unique in that it uses the small interwinding capacitance of the first and second windings to couple the switch on / switch off current to the base of the transistor allowing for a fast charge / discharge of base current, hence efficient switching of the transistor. This is less dissipative and provides stiffer peak current base drive than most JT circuits which use just a resistor. The interwinding capacitance also effectively limits "on time" by discharging, thus preventing saturation, hence the high switching efficiency.

The XEE2 circuit adds a small capacitor across the bias resistor to effect fast switching. This is commonly called a speedup network in the art. There are even better ways to effect base drive, depends on the goal, which is never carefully or clearly defined.

There is more, if anyone is interested.


Offline conradelektro

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Re: Lasesaber strikes again. A joule thief king ?
« Reply #89 on: May 15, 2014, 07:31:41 PM »

A better way is to switch off before saturation and control the cycle by cycle charge into the inductor.


Well, nice idea, how can one do this? Do you have a circuit?

I think I want to do that with the adjustable narrow square wave from the MAX931 circuit. It is true that the 5 µA are lost, but it is very little in comparison to the energy needed to drive a 220 V 10 Watt LED lamp.

Keep the circuits coming, idle talk is useless.

Greetings, Conrad

Free Energy | searching for free energy and discussing free energy

Re: Lasesaber strikes again. A joule thief king ?
« Reply #89 on: May 15, 2014, 07:31:41 PM »

 

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