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Joule Thief battery charger

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Uploaded by on Mar 28, 2009

This is my first joule thief battery charger!
If you like it please rate!!!

  • likes, 3 dislikes

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Uploader Comments (Flux4Energizer)

  • how does the variable resistor affect the circuit?

  • @lokeycmos

    It's there to get the circuit in resonance and to get the leds turn brighter or dimmer

    Regards,

    Flux

  • Voltage, normal Joule Thief transistors die/stop at .84volts, but Germanium transistors die at .3volts, much more run time...

    You can also add transistors to increase output, or use a disposable camera coil or $3 10kv trigger coil and get well over 1000 volts. I get 1350 volts and lighting wireless LEDs and Neons, which has me now experimenting with wireless receiver circuits, to amplify, magnify.

    Cheers...

  • @LoneOarman

    Yes i've seen the new circuit with a trigger coil (most 4kv), but i don't have a trigger coil and i don't now where to get one here in holland.

    If you know where i can find someone one ebay or something which sells these coils and transistors i would like to hear it.

    I'm at the moment playing with a secondary JT. I want to light up aprox. 50 leds at full brightness but the challenge is i only want to use 1.5V at a maximum of 50 - 75 mA (or 3V at 25 - 35 mA).

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All Comments (32)

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  • Euuhhhh.

  • I don't question that the 400 LEDs are lit up with a single 1.5V cell. But it's a simple matter of physics and math that contradicts the "full brightness" term that was used.

    As I said earlier, all it needs is another 3 watts to be at full brightness.

  • That is not correct. With my joule thief, I can light up 400 leds using a 1.5 volt battery. Check my videos.

    Bill

  • Where to the capacitor and resistor connect to? I have put a 1k or so resistor and 10 uF capacitor across the 1 ohm resistor that was in series with the LED. The idea was to filter out the pulses that were across the LED and 1 ohm resistor. But I got the same reading with or without the resistor and capacitor. So I just measure directly across the 1 ohm resistor.

    I've read the posts in those blogs, and I'm not sure what the poster's objective was. The way they blogged was confusing.

  • I'm not sure what you mean by secondary JT. Ok, let's get some estimates of what is needed to "light up 50 LEDs to full brightness." A typical 5mm white LED is at full brightness when running at 20 mA. No matter whether they are connected in series or parallel, each white LED requires about 3.2V. So 3.2V times .02A is .064 watt. Multiply by 50 and you have 3.2 watts. But 1.5V times .075 A is only .1125 watts. You're still lacking over 3 watts. You're going to have to give up something.

  • You can go to your local Drug Store and they will have those disposable camera coils in the trash can, garbage, and will give them to you for free if you will ask. You can also try old TV HV coils or flyback coils. I have one that outputs 850volts with 3v input. I will send you links for the trigger coils that may ship to you in Holland., the 10kv are best, but keep in mind that wireless will work with just a few hundred volts.

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