Rolling your own electronics components can be fun, but can also help in explaining how certain items actually work. [Addie] from The Toymakers recently set off to figure out how capacitors work, by making her own.

She understood the general concept behind capacitors and how they are constructed, but she wanted to see how it was done first-hand. To construct her capacitor, she selected aluminum foil as her conductor, and saran wrap as the dielectric. She admits that her first attempt was a failure, but undaunted, she carried on. Friends suggested that her conductors were a bit too small to hold any reasonable charge, so she tried larger sheets of aluminum foil to no avail.

She kept at it and found success after using several feet of foil to construct her capacitor. She charged it with a handful of AA batteries and was excited to see her multimeter come to life when she touched the leads to the cap.

While you likely wouldn’t use a hand-made capacitor in your next build, it is a fun experiment to do with children interested in learning about electronics.

[via Adafruit blog]

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In keeping with our opinion that radio operators were the original electronic hackers here’s a guide to building your own transmitting air variable capacitors. Using some roof flashing, Plexiglas, and various fasteners [David Hammack] was able to make it work. It’s not a perfect solution but he has some ideas to make the next one better. Give this a try after you’re done tweaking your crystals and building input devices.

[Thanks Rich]

Most ICs need to be decoupled from their power supply, usually with a 0.1uF capacitor between each power pin and ground. Decoupling is usually used to remove noise and to smooth power fluctuations. Every project will need a few decoupling capacitors; our mini web server project has three ICs that require a total of 11. This can be an expensive part to buy in singles, so it’s crucial to stock up online. Read more about our favorite bulk through-hole and surface mount decoupling capacitors after the break. Read the rest of this entry »

The Leyden jar capacitor posted the other day fails to compare to what [FastMHz], one of the members over at the 4HV.org forums, has been busy building, a 24kj capacitor discharge bank. This capacitor bank will be configured for 4500v @ 2400uF and can be charged up slowly using microwave oven transformers. It can then release all its stored energy in under a millisecond through a triggered spark gap. This allows for some pretty big sparks as seen in this video, we are not sure about the laughing in the video maybe the power has gone to his head? Read the rest of this entry »

If you’re anything like us, you have a closet full of old electronics, some broken, some obsolete. You can stop using those as paperweights with the help of this guide that shows you how to recycle and reuse PCB components.

The first step of the process is finding electronics you don’t mind taking apart. Next place the PCB you’ll be stripping in a vice, with the components facing away from you and the solder side facing towards you. Grip the component you want with a pair of pliers, and apply a hot soldering iron to the solder that is holding the component. The solder will melt and allow you to safely and cleanly remove the component.

This process can be applied to virtually any component on an PCB, and the author of the guide, [Patented], got a lot of components this way, including resistors, capacitors, switches, audio jacks, and much more. Don’t forget to toss any free-floating metal or plastic parts in the recycle bin when you’re done. You can feel good about the fact that nothing was wasted, you found parts for your next project, and you cleared out some space.