"Joule Thief" - No IC and No Transformer





Introduction: "Joule Thief" - No IC and No Transformer

Yep, no transformer and no hard to get IC. But, ... two transistors and other parts are required. I actually found this circuit by accident while roaming Colin Mitchell's Talking Electronics website (talkingelectronics.com). This website is very rich with examples and explanations of a huge variety of circuits. In fact, this website is so abundant in circuits that later on, I couldn't find the circuit revealed here. Anyhow, I believe that the TE circuit can be considered "robust" as it works even if different parts are used.

Step 1:

Step 2:

With an ordinary red LED in series with the white LED, the circuit draws 15 milliamps @ 48 kHz.
But when using only the white LED, the circuit draws 17 ma @ 38 kHz.

Step 3:

The "Joule Thief" circuit using only easily found parts and no transformer might be attractive to many readers here. This is why I thought it was important to reveal this project.
But in my case, I am still tilted toward the simplicity of a "Joule Thief" circuit using little more than an IC and an Inductor, as revealed in my Instructable, "Joule Thief" Circuits - crude to modern...

Step 4:



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    I need your suggestion and help, from a source I am getting 100 mV and 50 microAmp (µA) not milliAmp (mA) current continuous mode. Can I use jewel thief circuit to light a LED. if yes please let me know the resistor in ohm, diode specification and led specification so that i can make the circuit and how many wire turns will be required. To enhance the density, can I use capacitor for this small production of what specification. Please help

    I don't think that I have any specific answer to your question that will allow you to do what you are hoping to do. But I did make a 0.35 V power supply that you might easily make for further testing. I measured 0.35 V across each of the lower 1 k ohm resistors. When I loaded the lowest 1 k ohm resistor with a 10 K ohm load, the voltage across the middle resistor measured 0.36 V while the voltage across the lowest resistor measured 0.34 V. So,... a 10 k ohm resistor across the lowest resistor should draw about 34 u amps, according to Ohm's Law. This is all that I can offer you at this time. In the worst case, maybe you could show that 100 mV @ 50 uA is NOT a very practical power source...

    0.3 V.jpg

    Is it possible to replace Q2 with a Darlington type of transistor ?

    What value of inductor should be used in case I want to power a 0.5W LED ?

    Except for maybe the LED, all the related parts are cheap. Why not start with the parts that work on a regular 3 volt white LED and see what happens. I suspect (but don't know) that you might want a 100 uH inductor instead of 330 uH. Or you could consider putting two higher inductors in parallel to both lower the inductance and resistance. Since the LED isn't ON 100% of the time, you might get away with using parts with a less than 500 ma rating. I don't, however, see any advantage to using a Darlington pair. If I were doing this, I would just start trying things out...

    Boost converter-y. Awesome.

    can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic

    I am not sure of your question about "exact circuit." Did you read all of my Instructables related to joule thief?

    You must give me your full name and mailing address for me to send you a joule thief ic. You can also try using my email address:
    theabundance@yahoo.com to communicate with me.

    Dave Kruschke

    can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic

    can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic