Joule Thief 101

[TinselKoala]

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

Watch the video.

Comments?

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]

Brad:

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.

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.

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.

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]

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]

Rusty:

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]

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