After I unsoldered the parts from my failed ‘noisy regenerative receiver’ circuit, I decided to build a more conventional regenerative receiver, one that uses a single transistor for the regenerative stage. I chose the circuit from a website that I had found, and saved the schematic. But I forgot to document the URL of the
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It has been a long time since I designed Blue Blinky; I just wanted to update it. I have used a 1 uF electrolytic capacitor for the timing capacitor, and it works just fine with the two 680k resistors to give about 1 per second flash rate. I got a bag of hundreds of multilayer
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I’ve built an FM microphone bug or transmitter before, but it’s been a very long time since I wound coils for one. Long ago I would wind too many turns on the coil and try it out. The usual outcome was the bug would be transmitting somewhere in the low TV channels 5 or 6,
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First off, I must state that the PSO is not the best solution for an audio oscillator. It uses only a single transistor, but it has a limitation that makes it put out a poor quality sine wave. As typical of the PSO, the sine wave becomes distorted because the loop gain is greater
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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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I finished gluing the 10 000 uF capacitors down to a piece of wood. I now have a Massively Parallel Capacitor Array (MPCA) Now the hard part comes: connecting all 150 of them up in parallel. I bought a whole box of 250 electrolytic capacitors on tape and fan folded. They were only ten dollars
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I once had this blogged in my watsonseblog, but I haven’t blogged it here. I’m trying to charge this Maxwell ‘Boost Cap’ or ultracapacitor with a solar cell, but the problem is that this cap is so ginormous that it takes a very long time to charge when the solar cell is putting out 100
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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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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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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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