I was watching this Youtube video of a Joule Thief that is used as an EMF detector. Actually it is detecting the electrostatic field, not the electromagnetic field. If it had a pickup coil instead of an antenna, then it would be detecting the electromagnetic field. Anyway, it looks like he is trying to trace
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When I work on a Joule Thief I need a power supply that will go all the way down to zero volts. Kirk pointed me to a high current power supply (6 to 8 amp) that puts out zero to 30V and uses a LM317. I have built a power supply that uses a LM317
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Kirk sent me a link to a simple, inexpensive L meter that uses your DMM as the readout (see side note below). I should say that eBay has more than one seller that sells the LC meter that’s on a small PC board with its own display, and runs off of the USB port. The
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I found some LED lights on eBay for under 6 dollars U.S. with free shipping. They’re shipped from Hong Kong, so it will take a few weeks to get here. They said sometime around the 4th of July. Wow! Instead of lighting up firecrackers, I’ll be lighting up LEDs!! They call these corn cob lights
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Yeah, that’s what I said: What’s soakage? Well, you can read more about that at the end of the multipage article here. He also discusses power storage, and most importantly, how not to measure leakage. The result is that the leakage of the wiring and test leads becomes noticeable, where one would never notice these
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This is the second one I’ve built. The first one I built is in my earlier blog – links to the schematic can be found there. I used the following parts: a 2N3906 for Q1, and PN2222A for both Q2 and Q3. R1 was 470 ohms, R2 was 10k and R3 was 8.2k. Both the
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I’ve blogged this project more than once in the past, (and here too), but I didn’t follow through with the circuit completed and installed in a DMM. Well, I finally got my act together and on the road, and finished the first working 1.5V to 9V DMM power supply. I thought about it and concluded
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Drawn May 14, 2013. I plan on building it soon. I think it would be better to replace the 82k with a 130k and use a smaller value pot, maybe 25k. I may have to use some 1% precision resistors and capacitors to get the frequency to be stable over a temperature range and supply
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I was wandering around the pages of the Modern Electronic Circuits Reference Manual, a 1200 page tome by Markus, when I happened to see this odd circuit for a signal generator (see the schematic). My curiosity got the best of me, and I knew I had to build one, since I have a whole lotta
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This is an old schematic that I drew in Apr of 2005 using SwitcherCAD III (now LTspice). It is taken from the board I built and put in service for several years as a LED test jig for testing the lifetimes of various white LEDs. Needless to say, most of the white LEDs lasted less
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