Joule Thief

[freepow]

@  DreamThinkBuild

When you say to charge cap fully it needs  5 time constants...  is that for any size  supercaps or just the 1500F ?

[Poit]

I built my first JT today ... yay for me

I feel like such a novice lol....

Does anyone recommend cool stuff to do with it? (besides the LED+JT)

Pete
P.S I applied it to my salt water battery setup, works great!!

[DreamThinkBuild]

Hi Freepow,

When you say to charge cap fully it needs  5 time constants...  is that for any size  supercaps or just the 1500F ?

You can put any capacitor into the formula.

Time constant = Resistance * Capacitor value

Five time constants represent a full charge but for purists it's about ten time constants. 

Here is a calculator on line:

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capchg.html

You just have to convert your F cap to uF for the above calculator:

http://www.unitconversion.org/electrostatic-capacitance/farads-to-microfarads-conversion.html

Hi IotaYodi,

3000F, you can make a nice pulse heater with that. You would need about 3v, 60 amps to charge the 3000F in 11 minutes. 6x6 .5v solar cells@7 amps (9 columns * 6 rows)=54 cells would do. If you have two caps while one is heating the element the other is charging it would reduce the time in half. You just need a switching circuit to cycle between charge to heat.

[freepow]

  Just a quick experiment...    I put   1x small copper pipe and  1x thin galv steel rod, both about 8" long
    into the ground giving me approx 0.95v at around 2 mA's and connected  1x 55F  2.5v Capacitor to 
    the earth battery, and charged cap for around       
    8 hours or so,  then took it in to power my  HV Joulethief with the 240v mains powered  (20x Led bulb).
    It lit all 20 Led's for about  3 minutes or so,  the cap was only charged to  0.952v,  but if I had charged
    2x of these caps in parallel, then connected them in series to the Joulethief, I would have had  1.9v
    Then my (20x Led bulb) would have been really bright, because it lights really bright with
    2 used AA's at approx  2.0-2.4v
    Here is a picture of my setup - diagram.

    Light using the earth for power,  free!
   

[Pirate88179]

@ Pete:

Welcome and good job on your JT.  You have already figured out something great to do with it by hooking to your home made battery.  The only limit now is the imagination.  Please continue to post about your experiments.

Freepow:

Yes, getting free energy from the earth is really cool isn't it?  I am still amazed by it.  Great job!

Bill