He uses my SJT circuit in his web page. https://devopedia.org/joule-thief-circuit
Archive for the ‘Building projects and kits’ Category:
2023-11-12 Knee High Bench Or Seat I Built
I made it out of an Ikea drawer that someone broke up and threw away. A little over 16″ high. The seat is the front of the drawer, about 9″ wide and 16″ long. Mostly a charcoal color. Took a few hours; I probably spent an hour finding the right pieces and pulling the screws
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2023-11-06 Reproduction Antique Radio Tubes and sets
I’ve been discussing the restoration of a hundred y.o. radio, and I thought about the retro light bulbs that look like incandescents but use LED filaments. Someone should make some old tubes that are actually using LEDs that look like the filaments, but just for decorative purposes. The glass envelope would look like the tube;
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2023-10-26 120V Heat Pump Water Heater Review
This HPWH made by Rheem requires only a 120VAC wall outlet. It requires a plastic condensate drain tube. It uses about 350 to 450 Watts. Theirs drew 65 kWh for the month of August. Their electric resistance water heater used 290 kWh average per month. The water heater cost $2533.00 from Home Depot. This article
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2023-10-22 Do-it-yourself Power Strips – True Story
We used similar “homemade” outlets on extension cords – we must’ve had more than a hundred around campus. But the fire inspectors wrote us up for using them in permanent locations under desks. We had to change them to commercial power strips. But I set up a temporary registration and add/drop classes area every semester,
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2023-10-01 Two 0.1 Ohm Resistors In Parallel To Make 0.05 Ohm
I found a way to make a 0.05 ohm resistor. I found some 0.1 ohm, 10W resistors and two of those in parallel will make 0.05 ohms. Voilá. The 10W is only if these 1 inch long resistors are bolted to a heatsink, so I guess they might handle 5 Watts free air. BTW, these
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2023-09-25 TV Modulator Ch 3 Doesn’t Work For Digital TV
I Came across this old analog TV modulator in a box of stuff, so I plugged it into my digital TV and powered it up, with some audio modulation on the input. I set the switch to channel 3, and then pushed 3 on my remote, but I got no carrier whatsoever on the TV.
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2023-08-26 FM Bug, Crystal Locked
From Talking Electronics. I’m not sure if this circuit can be frequency modulated the full amount for the FM broadcast band. It’s difficult to push a crystal off its resonant frequency. I’ll be trying it someday if I can find the right xtal. I would be more inclined to instead use a ceramic resonator. I
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2023-07-23 I Was Into Rockets When I Was A Kid
I joined the Reaction Research Society when I was a teenager. It’s a rocket club, still going strong: rrs.org. We went out to the Mojave desert to launch homemade rockets. Some went up to a mile high, some exploded on the launch pad. They used a mixture of powdered zinc and sulfur, which burns very
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2023-07-12 DC-DC Converters That Used Germanium Power Transistors
Me and my high school friend made a DC to DC converter that would give us 30 or so volts at a couple amps from a 12 volt battery. We used germanium power transistors which could not go much above 10 kHz. The Delco’s and the 2N458A’s were our favorites – we managed to push
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