I assembled a two transistor LED driver buck converter for dropping the 12V input down to the 3.2 volts needed for the LED. My problem seems to be that the circuit wants to act like a simple 22.2 mA current limiter, as if I took out the inductor and capacitor (the D1 is reverse biased
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From Watsonseblog Jan 2010: Very odd LED dropping resistor – edible! There are several others of the same genre on Youtube but this one has LEDs. Cool, an edible resistor! I remember that the stores sold a hot dog cooker that was just s simple box with a drawer and electrodes. It took about a
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This circuit was posted to the files section of the Yahoo group Joulethief (you may need to join to see this). I´m going to try to attach the pic but I couldn´t do it earlier, You might also be able to see the picture here. I built four versions of this circuit and made some
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One of the earliest germanium transistors was the 2N404. It became a popular transistor for use in projects after the demand for germanium transistors fell when Texas Instruments and other companies started selling silicon transistors (for more transistor history see here). I recently bought some germanium transistors labeled 2N404, but they seem to have much
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I had these pics of my JTs from 2009, both conventional and supercharged JTs. The conventional JT is lucky if it can be 50 percent efficient. My Supercharged JT will do upwards of 80 percent easily, using much less battery current while giving the same amount of light output. I believe I have seen only
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I was reading a post from a school teacher about wanting a subject for the class project. Bingo, I thought of something that had not really come up before: “How much does it cost to make a Joule Thief?” I guess it would be best to start with a BOM, or Bill of Materials. The
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Another pic from the past – Apr 2009. The 10 Farad supercapacitor powers the flasher brightly for 1 hour and dims for another 3 hours. The circuit consists of an astable multivibrator with unequal resistors to make it put out a short pulse every second or so. This is the three transistors to the left
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The 2N2222 and 2N2222A comes in, and has always come in a metal can package. The manufacturers came out with an equivalent that was much cheaper because it does not have the metal package, it’s a regular TO-92 epoxy package. The 2N2222 and 2N2222A specifications require a metal can package, so the manufacturers named the
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These tiny T231212T toroids from Surplussales.com are high permeability so it doesn’t take much wire to make a good Joule Thief coil. The core is less than a quarter inch diameter (here is a data sheet in .PDF.). Six inches of 30 AWG magnet wire trifilar wound, with two of the windings connected in parallel
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It will work with a few hundred millivolts.DAMASCHKE-064a-97ia-jmd
