In the world of electronics we have impedance; the combination of all forces which oppose the flow of electric current. Often times we have circuits with different impedances, 50 ohms for RF, or 75 for cable TV. It’s pretty important to use the right coax in these circuits, else you’ll be wondering why your RG-58 antenna feed line doesn’t give you anything good to watch.
It’s pretty important to match impedances when connecting different circuits. Apart from the obvious flaws such as a 50 ohm load blowing up a 300 ohm amplifier, there are subtler things such as signal reflection and destructive interference which might just be enough to break whatever it is your playing with. RF mosfets are not cheap! But how could we match impedances? Well we could always use a transformer, but those are rather expensive and bulky. What if we only have a box of resistors to play with? Continue reading “The pi pad”
Last week we covered diodes, specifically thermionic and PN junction diodes. But oh, there are more; and they’re special!
Continue reading “A bit more about the diode”
With the death of Heathkit looming in our minds it’s high time for a a heartwarming story. [Ronald Dekker] has done a wonderful job documenting the history of the E1T beam counting tube, detailing everything from the work led up to the invention of the tube to the lives of the inventors themselves.
For those who are unaware, the E1T is a rather strange vacuum tube capable counting from 0 to 9. While that’s nothing too special in itself, the tube also displays the numbers on a phosphor screen, much like a miniature cathode ray tube. In fact, this phosphor screen and the secondary emission caused by it is critical to the tubes operation. To put it bluntly, it’s a dekatron and a magic eye tube smashed together with the kind of love only a group of physicists could provide.
Now, who wants to have the honor of transposing Ronald’s story into a wikipedia article?
Most of you already know what a diode is, but how much do you really know about the device?
Continue reading “A bit about the diode”
[Overflo] recently tipped us about HackerspaceShop; his plan to help fund the Viennese and European hackerspaces by creating a marketplace for electronic kits. The idea is to not only sell kits, but to also create an easy way for others to sell their own kits through the platform, which is pretty awesome if you ask us.
Their kit they sent us to play with is a sun tracking flower developed by [daniel schatzmayr] in the metalab hackerspace. All and all, it’s a pretty awesome kit that’d be perfect for any geeky girlfriend, and of course, it’s arduino controlled. Whether or not that is a good or a bad thing is up to the hackaday trolls to decide, but it does have an FTDI header; something we’d personally like to see on a lot more of these electronic kits.
Currently there’s not to big a catalog on their site but hey, wickedlasers started out as a guy selling modified laser pointers and Hewett Packard started out as two guys selling a better function generator. It’s always awesome when a hacker uses their skills to become an entrepreneur, especially for a good cause.
Good luck [overflo]!
DIP, SOIC, BGA, MLF or QFP? None, so it seems.
This morning I received an email from Texas Instruments. Normally, these things go right into the spambox but this one was a bit unique. You can now buy some of TI’s IC’s without any packaging. Yup, just trays full of silicon squares. From TI’s point of view miniaturization has reached a point where that extra 0.1″ of PCB space is now too valuable to give to a piece of worthless plastic, and bonding micro-small wires to a silicon die is a feat that any manufacturer can preform with great accuracy, reliability and speed.
Whether this is a new paradigm in manufacturing or a premature April fool’s joke, if this process catches on smartphones just went from being almost unrepairable to 100% unrepairable, and ipod nanos might just start playing back 1080p video. It’s awesome and scary at the same time.
Now, are they crazy, or just ahead of their time? Tell us what you think.
[Gil] recently wrote in to tell us about some awesome research going on at UCLA. Apparently by layering some oxidized graphite onto a DVD and tossing it into a lightscribe burner, it’s possible to print your own super capacitors; some pretty high capacity ones at that.
For those that are unaware, supercapcaitors are typically made using two electrolyte soaked, activated carbon plates separated by an ion permeable film. Since activated carbon has an incredible surface area huge energy densities can be reached, in some cases 1kJ/lb.
Laser-formed graphite sponge replaces the activated carbon in the researchers’ printed capacitors. A video after the break discusses the whole process in moderate detail, meanwhile greater detail can be found in their two papers on the subject.
First one to print a transistor gets a bag of mosfets!
Continue reading “Print your own Supercaps”