He uses my SJT circuit in his web page. https://devopedia.org/joule-thief-circuit
Archive for the ‘Do It Yourself’ 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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2023-10-01 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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2023-08-26 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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2023-07-14 Solve The Resistor Cube Problem
Last year I tried redrawing the cube in two dimensions and I could see how the vurrents were splitting but couldn’t solve it. Now here is a simpler solution that doesn’t require a lot of effort with whatever. I built the cube from 1k resistors and measured the value from corner to opposite corner, and
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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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2023-06-24 Never Defeat The Fuse! Or Fusible Link
I saw that meme where some clown replaced the 30 amp fuse in his car with a live .22 long rifle cartridge. That was a disaster waiting to happen! This is a true story – mid 1970s. My neighbor bought his wife a new sleek red Trans Am, and really loved how fast it could
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