Joule Thief 101

[Magluvin]

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

Watch the video.

Comments?

Thats and impressive demo lighting those 12v led strips, of which I have 3 rolls of here.  The strips have current limiting resistors between every few leds, like say 3 for blue or white in series with a resistor.


if it is radio freq he is absorbing, looks maybe am. Or possibly 60hz?  Fm wouldnt have coils like that I think.

Thanks for posting.

Mags

[Magluvin]

Thats and impressive demo lighting those 12v led strips, of which I have 3 rolls of here.  The strips have current limiting resistors between every few leds, like say 3 for blue or white in series with a resistor.


if it is radio freq he is absorbing, looks maybe am. Or possibly 60hz?  Fm wouldnt have coils like that I think.

Thanks for posting.

Mags

In fact, that looks like enough to power a cell phone, according to the strip around his brother there.  Might not be 2A like many newer chargers, but could charge probably slow charge one from what I know.

Mags

[Nink]

In fact, that looks like enough to power a cell phone, according to the strip around his brother there.  Might not be 2A like many newer chargers, but could charge probably slow charge one from what I know.

Mags

They did not say what was in the coffee can in addition to the rectifier.  My guess is a capacitor that was charged over an extended period of time and then discharged in order to power the LED's.  A little bit of a party trick but not exactly a lie the LED's were being powered by harvested energy.

[MileHigh]

He should go beat up Clock Boy and then sail off in a balloon.

[gyulasun]

Self charging JT

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


Brad

Hi Brad,

From your video it seems the variable capacitor is not used for tuning the main coil on the ferrite rod antenna: I think you would  pick-up more power from the AM radio station  by resonating that coil at the 963 kHz (or so) AM broadcast frequency.

Also, the direction or orientation of the ferrite rod with respect to the location of the AM transmitter also counts in the amplitude of the received signal, you surely know this.  You may wish to connect the variable capacitor in parallel with the coil and find the maximum sinewave peak to peak amplitude at 963 kHz, watching the amplitude on your scope, while turning the board with the ferrite rod on it also for maximum amplitude. Sorry if you have done this or are aware of all this,  you have not mentioned or showed these yet.

Gyula