[Norman] put together a rather impressive 22,500 uF capacitor bank. In addition to find things to torture with the strong magnetic field generated by a sudden discharge, he’d like to measure the current pushed from the device. He’s found a way to do this using a digital storage oscilloscope. To protect the oscilloscope [Norman] built his own interface box that includes a 50x voltage divider, and interfaces a current sensor called a Rogowski coil. When it comes time to run the experiment, he turns the safety lock-out key on the bank charger, then discharges the stored potential with the flip of a switch.
Take a look at the video after the break to see soda cans and hard drive platters mangled by the device. The oscilloscope measures the output near 10 kA, giving [Norman] the data he set out to capture. He’s entered this project into the Tektronix contest where it’ll compete with the piano tuner and laser light show tester just to name a few.
posted Feb 15th 2011 2:26pm by Mike Nathan
filed under: news
[Jeri Ellsworth] recently released another video in her “A-Z of Electronics” series – this time Capacitors are the subject. As a penance for my boneheaded AC Capacitor suggestion yesterday (I swear it was lack of sleep talking), [Caleb] suggested that I be the one to write this article. Since I’m not an electrical engineer (I majored in Comp Sci), I enjoy watching these videos, and I share them with individuals who are new to electronics. [Jeri] always presents the subject matter in a clear and concise manner, so the subjects do not seem daunting or intimidating.
She briefly discusses the early development of capacitors, including Leyden Jars, then focuses on modern capacitors and their usage. She covers wiring capacitors in circuits, demonstrating the difference between series and parallel configurations, as well as how electrode distance affects capacitance.
If you have a spare minute, be sure to check out her current video as well as those she has previously released.
Audio Crossovers are an essential tool for any high end speaker system. Because most individual loudspeakers are unable to cover the entire spectrum of audible sound as well as multiple drivers are, it is necessary to split the input signal into low and high frequency parts. When a friend of [Anthony]‘s was about to send off a classic Klipsch AA Crossover to be repaired professionally, [Anthony] insisted it was possible to save some money and do it himself.
The oil can capacitors of the Crossover had gone bad, so a new set of metalized polypropylene capacitors were ordered to pick up the task. After carefully removing the old caps, [Anthony] assembled the new set on a breadboard, and mounted the board to the old Crossover base (along with some tasteful McDonalds straw spacers). The entire process is detailed on his blog, and we are sure his friend saved a good deal by this home repair method. Capacitor issues are a commonproblem in repairing electronics new and old alike, and always a great place to start looking when devices start acting funny.
The ceiling fan in [Steve Vigneau's] bedroom started giving him trouble. It is normally operated using a remote control but that functionality had become pretty spotty. He cleaned the contacts on the remote but still had troubles that could only be fixed by power-cycling the fan itself. When it finally died he set out to repair the unit himself. Above you can see the controller board from the fan. It was a bit too complicated for [Steve] to troubleshoot so he figured why not just stop using the remote control and make it work with a couple of switches? A bit of research led him to some basic fan schematics that he used for a reference. He need to remove a couple of capacitors and wire them up with one switch for the fan and another for the light. Sure, there’s no settings for speed or direction, but [Steve] thinks he doesn’t need to change them and always has the option to add them in the future.
What weighs more than 500 pounds, produces 500 kilovolts, and we don’t recommend you try at home in any way shape or form? If you guessed a rock disaggregation device, you’re correct! We also accepted lightning generators as correct answers. Using high voltage electricity, a rock can be split apart down to its grains without destroying the precious minerals inside; unlike traditional grinding and mechanical techniques that often ruin the sample. All it takes is a massive hydro pole transformer, five 1uf 100 kilovolt capacitors, eight hand wound inductors, and two massive cojones to stand within 20 feet of the thing while it’s going off. Video after the divide.
The software end of things is a curious conglomeration but considering the hardware constraints [Daniel] made some great choices. He’s using MS-DOS along with LxPic for slide shows and Mplayer for video. The rest of the software gets him up on the home network and enables IR remote control via LIRC. All o this makes for a beautiful product (video after the break includes some Doom footage) and the package is pulling just 40W when in use.
posted Jul 18th 2010 1:18pm by Mike Szczys
filed under: news
[Daniel Eindhoven] put together this 11,344 Joule capacitor bank that he says would be perfect for weapons such as a rail gun, coil gun, or electrothermal-chemical gun. He machined a couple of aluminum plates to act as a positive and negative bus. The two are separated by a denuded sheet of PCB (making us wonder how he got the copper to peel off like that). Once charged there’s the little problem of how to discharge the system without getting bit, which [Daniel] solved by building a pneumatic switch. We didn’t find the test-fire footage very interesting but we did embed the demonstration of his switch after the break.
Ever wondered how expensive versus cheap multimeters hold up to abuse? [Dave] gives us a pretty good idea by, well, blowing them up. He’s using a capacitor bank to put roughly 4.2 KiloVolts into the poor little meters. If you absolutely must skip to the multimeters, go to about 5:00. You really will miss out on some good stuff though.
