I downloaded Stiffler’s SEC (Spatial Energy Coherence) .PDF and I found this schematic on P.47. It’s supposed to be for testing how bright LEDs are with a very short pulse. I found the circuit to be designed for danger; the same high voltage that appears across the primary (collector connected) winding also appears across the
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There’s no law that says that you have to have a ferrite toroid or any core material. Air core works, but the coil has to have many more turns, which makes it bigger and bulkier. But if the space is available, there’s nothing wrong with using a reasonably thick wire for the coils to keep
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I got a bunch of BC337-40 transistors; I don’t know why since I already have hundreds of BC338s and I haven’t really used a lot of them in years (see note). I have been using the BC337-25s because I felt that it was more representative of what the average transistor is going to be when
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I made this and I used an old HP 721 power supply set at 31 volts to power the LEDs. The 8 LEDs on each side of the middle are in series and add up to about 25 volts. The two sides are then connected in parallel. The 721 PS is set for 30 mA
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I received a Google Alert with a link for this Youtube video of a JT powering a LED night light. I have some thoughts that I’d like to share. A LED or three in a night light may take only a quarter watt or less, if run from a battery. But when run from the
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I received the following comment from Mayank and this is the reply to his comment. Hi Watson, I have a 1V, 3A solar panel that I want to use to charge 6V SLA battery. I checked some other circuits on the web and they use big torriod cores with 2N3055 transistors. Can I use a
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On occasion I see others refer to the Joule Thief and flashlight (torch) page of talkingelectronics.com. He has many comments, some good, some not so good, and some that miss the mark. Someone recently mentioned the Circuit B, which is shown in one of the pictures. He talked about increasing the efficiency a lot by
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Have you read the Joule Thief topic in Wikipedia? I think it’s poorly written and lacking in comprehensive information,. It reminds me of the blind men and the elephant: one blind man felt the elephant’s trunk and said the elephant is like a snake; another blind man felt the elephant’s tail and said the elephant
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This is a picture of an almost dead white three chip LED. The white phosphor has mostly disappeared, leaving the blue LED chips showing through. This has thousands of hours on it, but nowhere near the 100,000 hours that they are claiming LEDs last. I have tested a few dozen white LEDs and all of
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QS has added two nice little flashers to his web page. The first, a Simple JT Flasher, uses a regular 1.5V Alkaline cell. The second uses a rechargeable cell, and recharges it with a solar cell. I think I would not consider using the solar cell and rechargeable battery on a flasher. Why? Well, my
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