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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...
<p>Hello!</p><p>I designed the pc board for the first circuid.</p><p>You can download this design here:</p><p><a href="http://www.mediafire.com/download/s7lm6f8286t0iay/Joule_thief.zip" rel="nofollow">http://www.mediafire.com/download/s7lm6f8286t0iay/...</a></p><p>It works fine.</p>
<p>I need your suggestion and help, from a source I am getting 100 mV and 50 microAmp (&micro;A) 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</p>
<p>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...</p>
<p>Is it possible to replace Q2 with a Darlington type of transistor ?</p><p>What value of inductor should be used in case I want to power a 0.5W LED ?</p>
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.
<p>can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic</p>
I am not sure of your question about &quot;exact circuit.&quot; Did you read all of my Instructables related to joule thief?<br><br>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:<br>theabundance@yahoo.com to communicate with me.<br><br>Dave Kruschke<br>
<p>can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic</p>
<p>can you give me exact circuit which you implanted on breadboard without ....and if possible please send me a jule thief ic</p>
<p>If you are interested in trying out the 5252F IC &quot;joule thief&quot; chip, I'll send you one for free. Just email your mail address to my email address: theabundance@yahoo.com</p>
<p>Hi Dave,</p><p>I have looked over and read you comments on the #2 circuit. You spoke about using 3 volts temporarily and found the LED or LED's were brighter. Im looking to light a few LED (more the better). would your circuit stand 3volts on a continuous basis? would I wire the LED's in series or parallel? </p><p>You will see my instructable about charging AA Alkalines. The unit is working flawlessly give it a look. </p><p>Luckily I have access to many &quot;used/dead&quot; AA's, my apartment complex has 350+ units and each unit has 2 AA in the carbon monoxide detectors. Thus I get as many as I wish. Im not sure how long that will last but I'd like to build a few Joule Thief circuits and use them up. Bryan</p>
<p>Thanks, Bryan. I would definitely start out by wiring the LEDs in series, not parallel. I believe that the &quot;final&quot; transistor is rated for about 1/2 watt. This would add up to powering a bunch of LEDs, provided the circuit continued to oscillate. I suspect that a modest amount of hands on trials would quickly answer your questions much better than my speculations...</p>
Winding a toroid is really time consuming , so your instructable saved my day - literally ! - I made it in less than 1 minute and it's more efficient than my toroid based joule thief !
And now, I recently had a reader has ask me where I could put a photoresistor in the two transistor &quot;joule thief&quot; circuit to make the circuit turn off in light and turn on in darkness. I really didn't know but wired a photoresistor between the B plus and the base of the PNP transistor, Q1 (see first schematic below). This sort of worked but light didn't always shut of the LED - not good enough. I then added another transistor to turn on and off the circuit, where this transistor is controlled by the CsS Radio Shack style photocell and a 10k ohm pot (old volume control). This seemed to work fine as the light/dark trip point could be easily adjusted by the pot (see second schematic below)...
And now, I recently had a reader has ask me where I could put a photoresistor in the two transistor &quot;joule thief&quot; circuit to make the circuit turn off in light and turn on in darkness. I really didn't know but wired a photoresistor between the B plus and the base of the PNP transistor, Q1 (see first schematic below). This sort of worked but light didn't always shut of the LED - not good enough. I then added another transistor to turn on and off the circuit, where this transistor is controlled by the CsS Radio Shack style photocell and a 10k ohm pot (old volume control). This seemed to work fine as the light/dark trip point could be easily adjusted by the pot (see second schematic below)...
I recently had a request for info on how to run more than one LED off of the two transistor Talking Electronics circuit using only one 1.5 volt AA battery. <br> <br>I didn't want to use a hook up with LEDs in parallel because I might have to use wasteful dropping resistors. <br> <br>Actually I wanted to make my &quot;new&quot; circuit as much like the circuit from Talking Electronics that I had used for this Instructable. <br> <br>I replaced the single LED with a string of 8 Green LEDs and they all lit up, but they were a little dimmer. So, at roughly 2 volts per LED, maybe the voltage supplied to the LED string was about 16 volts. I then connected a Red LED to the coil-transistor collector connection. I did this to make sure I had DC voltage to measure with my meter. The meter was connected to the free negative end of the LED and also the battery negative. I measured 14 plus volts here. And, if I add 1.6 volts for the Red LED voltage drop, I get pretty close to 16 volts DC. <br> <br>Then I temporarily used 3 volts instead of just 1.5 volts for the battery power and all the LEDs lit up and were much brighter. <br> <br>Finally, I disconnected all the green LEDs, installed the 1.5 volt battery and measured the voltage again and got over 21 volts. Adding 1.6 volts for the Red LED voltage drop, I might have a maximum voltage of 23 volts &ndash; just with one AA battery. <br> <br>Dave <br>
Bravo!!<br> Add my sensor version and you could have a free night light out of 'waste'!!<br> <br> reg<br> ketan<br> -----<br> &quot;May the good belong to all the people in the world.<br> May the rulers go by the path of justice.<br> May the best of men and their source always prove to be a blessing.<br> May all the world rejoice in happiness.<br> May rain come in time and plentifulness be on Earth.<br> May this world be free from suffering and the noble ones be free from fears&quot;<br> ---- Vedic blessing
Thanks for sharing your Vedic blessing...
Hello nice writeup but you do know you can achieve this Joule Thief circuit with one Transistor and no Capacitor. Also the &quot;Transformer&quot; you claim not to use is an Inductor in the circuit you made. The only difference is that a person can easily make a Transformer rather than an Inductor and that the Inductor uses less space compared to a Transformer. I myself made an interesting Joule Thief only using one simple IC, a LED, and a source of energy above .5 volts. It can light up several LED's without any problems, too. I would show this circuitry but not a lot of people are into it even though it takes less room than any Joule Thief made so far.
A transformer is two inductors coupled together. They have different properties.
You have some good points. However, one of my main goals with my two &quot;Joule Thief&quot; projects was to find, test and share &quot;Joule Thief&quot; circuits that don't require bulky transformers that has to be wound by hand. In both projects, I used a cheap, &quot;less than a dollar&quot; inductor that comes ready made and is the size of a 1/2 watt resistor. I had thought that some readers might prefer this to winding a transformer. <br>Moreover, It sounds like you also might have a circuit (&quot;simple IC and an LED&quot;) that meets my goal of not requiring a transformer...

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