Homemade High Voltage Caps

Do you happen to have any 15,000 volt capacitors sitting around? [Ludic Science] didn’t so he did the next best thing. He built some.

If you understand the physics behind a capacitor (two parallel conductors separated by a dielectric) you won’t find the build process very surprising. [Ludic] uses transparency film as an insulator and aluminum foil for the conductive plates. Then he wraps them into a tube. He did throw in a few interesting tips about keeping the sheets smooth and how to attach the wires to the foil. The brown paper wrapper reminded us of old caps you might find in an antique radio.

The best part by far, though, was the demonstration of drawing an arc from a high voltage power supply with and without the capacitor in the circuit. As you might expect, playing with a few thousand volts charged into a capacitor requires a certain amount of caution, so be careful!

[Ludic] measured the capacitance value with a standard meter, but it wasn’t clear where the 15,000 volt rating came from. Maybe it was the power supply he used in the video and the capacitor could actually go higher.

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Homebuilt 30kV High Voltage Power Supply

If you have need for 30,000 volts to launch your ionocraft (lifter) or power other DIY projects then shuttle over to RimstarOrg’s YouTube channel and checkout [Steven Dufresne’s] homebuilt 30kV power supply. The construction details that [Steven] includes in his videos are always amazing, especially for visual learners. If you prefer text over video he was kind enough to share a schematic and full write up at rimstar.org.

The power supply can be configured for 1.2kV – 4.6kV or 4kV – 30kV at the output while requiring 0-24V DC at the input. In the video [Steven] tries two power supplies. His homemade DC bench power supply at 8V and 2.5A and also a laptop power supply rated at 20V 1.8A DC. A couple of common 2N3055 power transistors, proper wattage resistors, a flyback transformer and a high voltage tripler is about all you’ll need to scrounge up. The flyback transformer can be found in old CRT type televisions, and he does go into details on rewinding the primary for this build. The high voltage tripler [Steven] references might be a bit harder to source. He lists a few alternates for the tripler but even those are scarce: NTE 521, Siemens 76-1 N094, 1895-641-045. There are lots of voltage multiplier details in the wild, but keep in mind this tripler needs to operate up to 30kV.

Join us after the break to watch the video and for a little advice from Mr. Safety.

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Homemade Silicon Carbide LED

Here’s an LED indicator which was made at home out of a Silicon Carbide (SiC) crystal (Internet Archive Mirror). The concept is simple, but a bit of trial and error goes into getting that tiny amber spot to light up.

The guesswork comes in finding the right piece of crystal. First [KOS] broke it into tiny pieces, then he started poking the chunks with electrified probes to see if he could get some light out of them. Once an active area was found he needed a base for the crystal. The image above shows the two nails which he used. This provides a large mounting area that also acts as a heat sink to make sure the LED won’t burn itself out. There’s a solder blob which he kept molten with his iron until the crystal could be pushed into place. That holds it securely as the pin which serves as the cathode is positioned.

The whole setup is soldered to some protoboard and is ready to use. This is the second time we remember seeing this technique used to fabricate LEDS. The first time was an accident.

Homemade Bokode

[vimeo http://vimeo.com/6803291%5D

We’ve recently been getting a lot of new comments on our Bokode post from a while back, and with good reason.  [M@] has managed to find a way to replicate Bokode at home, using $0 worth of equipment (before the price of microprint). To accomplish Bokode at home, it seems all you need is and old webcam lens assembly and an LED.  Of course the his version is not as thin as a regular barcode so it probably wont be replacing anything in the near future, but the concept of from MIT to home within such a short period of time is amazing.