I was observing this video, and I saw that the 2N3904’s collector was connected to the negative and LED cathode, and the emitter was connected to the coil winding and LED anode. But I was surprised that when he connected it up, the LED lit up. Weird. But when he tried it with the 2n2222A
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Sometimes the circuit works all the time without a bypass capacitor. Sometimes it works most of the time without a bypass capacitor. Sometimes it doesn’t work at all without a bypass capacitor. As you can see, this chip didn’t have a bypass capacitor when the PC board was originally designed. Apparently the chip worked but
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Here is my latest germanium Joule Thief, shown squeezing the last few hundred millivolts out of the Energizer Bunny (“It just keep going and going…”). This is a real Zombie Battery Killer – that last half volt left after the regular silicon JT has given up is now sucked out, down to less than0.2V.
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In an earlier blog a commenter asked asked a question about how much inductance a Joule Thief should have; is there too much or too little. Well, I assembled and experimented with this Joule Thief to find out how little was too little. I cut of two 16 inch (40 cm) lengths of 30 AWG
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The photo is of one of my Supercharged Joule Thief circuits that I built a few years ago (see link at the end). This one has a supply current of 70 mA at 1.5V and a LED current of 25 mA at 3.3V (actually 25 millivolts measured across the 1 ohm [2 resistors] in series
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Reasons to not use a 2N3904 in a Joule Thief or other high current circuit I’ve said this more than just a few times before: when used in a Joule Thief circuit, the 2N3904 is pushed beyond its ratings and gives below standard performance. The maximum ratings for the 2N3904 are 200 milliamps collector current,
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DMMs All Over The Place – I have more than a half dozen of those cheapo Cen-Tech DMMs from Harbor Freight laying around my house, and I use them a lot for checking the AA and AAA cells that I’m constantly trying to drain with my germanium Joule Thiefs with their multicolored LEDs, of which
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I was discussing with Aki (theledart.com) his JT blinker, which uses a single winding coil, two transistors for the “JT” V booster, and two transistors in an astable multivibrator to blink the “JT”. He asked me to include the schematic. The first circuit boards that I had made from ExpressPCB.com used an astable multivibrator. I
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I pulled these Siemens DL 2416 from an old PBX. They are seated into an 18 pin right angle adapter that reduces the size down to the standard 0.3 inch wide pattern. I found the datasheet for these online. Each character of the four character display consists of small segments of red LEDs. There is
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I blogged Anton’s HV JT and noticed that it uses a 2SC945. I googled for 2SC945 datasheet and found a .PDF of the datasheet from NEC. It showed that the absolute maximum collector current is 100 mA, which is way too low for a Joule Thief, which needs several hundred mA. I scrolled down to
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