Author Topic: Joule Thief 101 (Read 937742 times)

Pirate88179 · « **Reply #480 on:** February 27, 2016, 04:50:50 AM »

Quote from: MileHigh on February 27, 2016, 01:44:39 AM

Smoky1:

Now I am going to play devil's advocate:

So let's assume for the sake of argument that you get better run times for the LED in this stable resonance/oscillation mode. It's a definite possibility, you never know.

So let's go back to something I said: The transistor briefly "oscillates down in resistance" and conducts and when that happens the LED goes off and the coil starts to energize. Then the transistor briefly "oscillates up in resistance" and the coil dumps some energy into the LED to light it up.

So you energize the coil in "small sips" and then the coil dumps those small sips of energy into the LED through "resonance."

When you strip that down to the bare bones, it's just like a DC-to-DC converter that pulses a coil for a very short time at a fairly high frequency and then dumps that energy into an output capacitor. I think a typical pulsing frequency is around 60 kHz and they only pulse the coil for a fraction of a time constant for the maximum efficiency (reducing i-squared-R losses.)

So just like you can buy a small very high efficiency DC-to-DC converter that switches at 60 kHz, you can buy a small very high efficiency DC-to-current converter that switches at a high frequency and the current output can be set to drive an LED.

So perhaps behind all the smoke and mirrors about a "resonant Joule Thief" the basic operating principle is essentially very similar to how a DC-to-DC converter operates. The fundamental principle is better efficiency through very small sips of energy that are then sent to the LED. This reduces resistive losses in the main L1 coil.

MileHigh

MH:

Now you are talking. You see, back in the "old days" us JT experimenters were told that this circuit is nothing new and does nothing unknown...or words to that effect. My response was always something like....OK, then if this is known, why do we not see this used commercially then? Because, at that time, members were really lighting some leds up for a very long time on a single AA battery.

Well, it was not too long after that when we began to see led garden lights that were solar powered. Remember when those first appeared? Of course, we could not help but take a few apart to see what was happening there and, low and behold, there was a chip that when we looked at the specs, was basically a solid state JT circuit. Then, some companies (China, of course) began to hide this chip under a blob of gray epoxy.

Now, I am not making any claims that our researching and playing with the JT circuit led to their commercial use but, the timing was interesting in that it removed my argument I used with you expert electronics guys.

So, I began to research some chip JT's and bought about 40 of them, along with some others and, they do work quite well. I also have a few dc to dc converters that perform well as a JT circuit.

I was corresponding with MarkE about the direction my interests had taken and he said he was working on something that was very efficient using a new chip. Well, about 3 weeks prior to his death, he pm'd me with the info on that chip and I am going to get a few to play with. I still have his pm saved here.

I know that you have always liked the good old 555 timer but now, as far as I can tell, we have some new technology that is better and more efficient (for this application) and will do everything we were doing in a much smaller package without winding any wire, ha ha.

So, I think it is a good idea to research what is now available and we can test these new chips. I do not know this for a fact but, I suspect that somewhere in that silicon there is something that adjusts the base voltage as the input voltage drops..... The tech for those garden lights is now getting a bit older but really, I have to say that for what they do, they do it very, very well. Also, I love how the prices have dropped since their introduction. Now, you can get an led garden light, complete with solar cell and charging circuitry and JT chip...including battery, and led, and an attractive case for less than $3.00. It was not that long ago we were paying more than that for a single led, ha ha.

So, we shall see what happens.

Bill

tinman · « **Reply #481 on:** February 27, 2016, 07:38:51 AM »

Self charging JT

https://www.youtube.com/watch?v=tx3bpSKRuF0

Brad

sm0ky2 · « **Reply #482 on:** February 27, 2016, 09:38:52 AM »

Quote from: tinman on February 27, 2016, 07:38:51 AM

Self charging JT

https://www.youtube.com/watch?v=tx3bpSKRuF0

Brad

hmm,.. I wonder what would happen if you had a couple thousand of these....

sm0ky2 · « **Reply #483 on:** February 27, 2016, 09:52:00 AM »

@ Bill

the "timing" was also interesting with the LED lightbulbs, and several other places JT's are now found

it could make a fairly convincing argument that these did not exist before the JouleThief fad occurred.

tinman · « **Reply #484 on:** February 27, 2016, 03:02:32 PM »

Quote from: sm0ky2 on February 27, 2016, 09:52:00 AM

@ Bill

the "timing" was also interesting with the LED lightbulbs, and several other places JT's are now found
it could make a fairly convincing argument that these did not exist before the JouleThief fad occurred.

Blocking oscillators have been around since the 70's.
The great John Bedini was not the first to build/design a transistor switched pulse motor either--he just tried to lay claim to that.

Brad

MileHigh · « **Reply #485 on:** February 27, 2016, 03:54:22 PM »

Quote from: tinman on February 27, 2016, 07:38:51 AM

Self charging JT

https://www.youtube.com/watch?v=tx3bpSKRuF0

Brad

Are you sure about that? The signal you show is 300 millivolts peak-to-peak. That's lower than a diode threshold. Have you traced a rectified version of the signal to the battery if that is indeed possible? Is it possible that your supercapacitor is self-charging?

tinman · « **Reply #486 on:** February 27, 2016, 05:36:27 PM »

Quote from: MileHigh on February 27, 2016, 03:54:22 PM

Are you sure about that? The signal you show is 300 millivolts peak-to-peak. That's lower than a diode threshold. Have you traced a rectified version of the signal to the battery if that is indeed possible? Is it possible that your supercapacitor is self-charging?

Well MH,im going to say im a bit !er yea

! on this one.
First up-and im not sure on this,or why-->the EM wave form from the radio station is all above the ) volt line-all DC,as can be seen on the scope shot below. I have dropped the 0v line by 2 divisions.
Second-i have ran it through 12+ cycles now,and it still keeps charging.
Third-i has placed a clip lead across the cap,and drained it completely. When the shorting lead is disconnected,the cap only recovers to around 12mV. But once i hook the circuit back up,it starts charging again,and will keep rising to about 220mV,and then the circuit starts to self oscillate again--and the cycle continue's.

The circuit is as below,and the scope placement that is showing the waveform on the scope.
Are AM radio waves a modulated DC wave,or are they a modulated AC wave? If the wave is DC modulated,and we have a change in amplitude(change in time),then we need no rectification,as it is already a DC wave form--an AC wave form with a DC offset?.
Other than that,im not sure. The only thing left to rectify the wave form is the transistor-some how?.

Brad

P.S
In regards to your question-have i traced a rectified version to the battery(cap in this case).
As you can see in the schematic,the scope is across the cap/coils series.
Oh,and the scope is inverted.

Nink · « **Reply #487 on:** February 27, 2016, 07:31:48 PM »

Maybe take the antenna off your electronics kit and throw the circuit in the microwave.

Lidmotor · « **Reply #488 on:** February 27, 2016, 07:45:21 PM »

Brad:
This is what I have been trying to do for years with zero success. I don't have a strong enough AM station near me. Congratulations on doing it. Please make sure that you are not getting any energy from the scope ground lead A ways back a bunch of us tried to replicate Dr. Stiffler's PSEC only to find out the power came from the scope ground he had hooked up.

To really convince people what you say is actually happening you will probably have to take the whole setup outside. I hate to say that but I see it coming. If you are getting that much energy into the system without a big/long antenna then you have stumbled onto something wonderful. Frankly even if the energy is coming from somewhere else I would like to know about it anyway.

MH:

I have been looking at that 'out of the box' circuit you presented and backed away from it. Too much work and not enough fun factor for a hobby guy like me with poor test equipment. I did try something a little different based on it though. I built a simple flip flop circuit and drove two separate NPN transistors off that. The NPNs pulsed two 1mH chokes with leds across them backwards to make the light. I powered the flip flop with a 3v coin cell and the inductor circuit with AA. I made an interesting experiment but was horribly inefficient.
Here it is and what it looked like on the scope: https://www.youtube.com/watch?v=_X_g52LsVnU

Pirate88179 · « **Reply #489 on:** February 27, 2016, 10:26:15 PM »

Quote from: Lidmotor on February 27, 2016, 07:45:21 PM

Brad:
This is what I have been trying to do for years with zero success. I don't have a strong enough AM station near me. Congratulations on doing it. Please make sure that you are not getting any energy from the scope ground lead A ways back a bunch of us tried to replicate Dr. Stiffler's PSEC only to find out the power came from the scope ground he had hooked up. To really convince people what you say is actually happening you will probably have to take the whole setup outside. I hate to say that but I see it coming. If you are getting that much energy into the system without a big/long antenna then you have stumbled onto something wonderful. Frankly even if the energy is coming from somewhere else I would like to know about it anyway.

MH:

I have been looking at that 'out of the box' circuit you presented and backed away from it. Too much work and not enough fun factor for a hobby guy like me with poor test equipment. I did try something a little different based on it though. I built a simple flip flop circuit and drove two separate NPN transistors off that. The NPNs pulsed two 100 mH chokes with leds across them backwards to make the light. I powered the flip flop with a 3v coin cell and the inductor circuit with AA. I made an interesting experiment but was horribly inefficient.
Here it is and what it looked like on the scope: https://www.youtube.com/watch?v=_X_g52LsVnU

Rusty:

Yes, that was my concern. Maybe there is a "better way" to do this but it is beyond anything I would know how to do.

Bill

TinselKoala · « **Reply #490 on:** February 27, 2016, 10:32:35 PM »

http://www.ktvn.com/story/31260413/13-year-old-creates-energy-harvesting-device

Watch the video.

Comments?

Quote

The harvester conducts radio waves, thermal, and static energy, and turns it into electricity.
"This wire takes energy from the air."
And the inside the coffee can,
"We turn it from AC to DC."

MileHigh · « **Reply #491 on:** February 27, 2016, 10:45:36 PM »

Brad:

Quote

First up-and im not sure on this,or why-->the EM wave form from the radio station is all above the ) volt line-all DC,as can be seen on the scope shot below. I have dropped the 0v line by 2 divisions.

It's quite obvious why there is a DC offset on the waveform, you should look for it.

Quote

Second-i have ran it through 12+ cycles now,and it still keeps charging.
Third-i has placed a clip lead across the cap,and drained it completely. When the shorting lead is disconnected,the cap only recovers to around 12mV. But once i hook the circuit back up,it starts charging again,and will keep rising to about 220mV,and then the circuit starts to self oscillate again--and the cycle continue's.

I am not sure that you can rule out self-charging yet. I am not sure how it works, I read about it once but I forget. If it is related to ionized air molecules both dropping off electrons on one terminal and picking up electrons on another terminal then perhaps you need to have the cap terminals connected to two 12-inch lengths of bare wire that run parallel to each other to facilitate the self charging. That might emulate the amount of wire in the setup. I am taking a guess here.

Quote

Are AM radio waves a modulated DC wave,or are they a modulated AC wave?

There is no such thing as a "DC wave." It's an amplitude modulated AC wave and what is really cool is that you can see the amplitude modulation right on your scope waveform. I am assuming that you are fairly close to the transmitter, perhaps less than 10 kilometers? Just a wild guess.

Quote

In regards to your question-have i traced a rectified version to the battery(cap in this case).

That would be interesting to see. If you replace the cap with a 100K resistor I am assuming that you will see something across the resistor.

MileHigh

Lidmotor · « **Reply #492 on:** February 27, 2016, 10:46:23 PM »

Bill:

What I have learned with this 'hobby' is that you have to be very honest with yourself. What is possible at my level of understanding and ability is perhaps not what can be done by someone else with better understanding and equipment. In order to keep the hobby fun and interesting I can't take on projects that are over my head that may or may not work.
I'm sure that there will be better JT type LED drivers developed but probably not off some guy's kitchen table using a Harbor Freight multi meter.

--Rusty

MileHigh · « **Reply #493 on:** February 27, 2016, 11:09:04 PM »

Rusty:

Quote

I have been looking at that 'out of the box' circuit you presented and backed away from it. Too much work and not enough fun factor for a hobby guy like me with poor test equipment. I did try something a little different based on it though. I built a simple flip flop circuit and drove two separate NPN transistors off that. The NPNs pulsed two 1mH chokes with leds across them backwards to make the light. I powered the flip flop with a 3v coin cell and the inductor circuit with AA. I made an interesting experiment but was horribly inefficient.
Here it is and what it looked like on the scope: https://www.youtube.com/watch?v=_X_g52LsVnU

No problem. For what it's worth, I thought of the perfect "big fat low resistance toroidal coil" to do the experiment in one's head. Think of a surplus store big step-down transformer, a biggie the size of two fists. It could be 120 to 12 volts or even preferably 120 to 6 volts. The low-voltage coil would potentially make for a viable coil. You can't forget that regular laminated transformers are the same as toroidal transformers.

Even with a big fat transformer as the big fat inductor, there are no guarantees that it would even work as a kind of "concept car." Now, if next month commercially available high-temperature super-conducting wire becomes available, then we might really have something to talk about.

MileHigh

Nink · « **Reply #494 on:** February 27, 2016, 11:27:36 PM »

I like this one https://vimeo.com/57142186

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Author Topic: Joule Thief 101 (Read 937742 times)

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