Joule Thief

[dllabarre]

@ dllabarre

That is a very low voltage for a silicon transistor. Can you post a circuit diagram?

[xee2]

@ Pirate88179

This circuit runs for 30 seconds from the 0.047 F capacitor after the battery is removed. It is hard to show how bright the LED is during this time so I hope this video will help. The video starts when battery is removed. The LED is illuminating a piece of paper 6 inches in front of the LED. For the first 20 seconds the LED is bright enough to see what is on the paper. The coil is made with a 3.38" toroid but I think a Goldmine toroid will give same results. The time it runs should scale with the size of the capacitor. So your 0.47 F capacitor should run 10 times as long (about 3 minutes) and your 20 F capacitor should run 425 times as long (about 2 hours).

Sorry about video quality and codec, but it is hard to fit a good video into 300 kB.

EDIT: added photos at 5 second intervals

[Pirate88179]

xee2:

I tried posting this last night 3 times but it disappeared somewhere so, I will try to write this again.

Nice video, there was no problem with quality at all on my end.  It looked fine.  Way back in the very beginning of the EB topic, I used just a supercap (5.5 volt .22 F) and a red led (5mm) hooked to my EB.  I am going from memory here but I can look up those posts if it would help.  I remember charging it outside for a few hours and then bringing it in the house and setting it on my table in the kitchen.  It remained very bright for about 15 minutes or so and was still illuminated for about another 10 after that, but not bright enough to read from)  This was long before I ever heard of a JT circuit so it was just the supercap wired to the red led.

I never tried a regular led and longevity test with my JT and the 10 F caps...I was always using ultrabright leds (10 mm) and usually more than one.

I would like to charge up my 650 F cap and hook that to a regular led and run a time test on it.

If I can find a photo of the led on my table running off the small cap, I will add it here.

This was not long after I joined this forum and I did not know very much at all, not that I know a lot now, ha ha.  ***EDIT***  I had thought that was the .47 F cap but it was the one I got from a shake flashlight and it was .22F.

Bill

[Pirate88179]

One thing I have figured out that I didn't know then is how I could charge a 5.5 volts cap from my EB which , at that time, only put out about 1.6 volts.  That 1.6 volts was measured on my meter and did not include all of those spikes that somehow the cap uses and stores.  I see the same thing on my 2.7 volt 650 cap which charges from the electrodes which only reads about 2 volts on the meter.

Bill

[stprue]

One thing I have figured out that I didn't know then is how I could charge a 5.5 volts cap from my EB which , at that time, only put out about 1.6 volts.  That 1.6 volts was measured on my meter and did not include all of those spikes that somehow the cap uses and stores.  I see the same thing on my 2.7 volt 650 cap which charges from the electrodes which only reads about 2 volts on the meter.

Bill

So with the spikes it is also capturing current/F, right?