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Electronics chit chat / Re: harmonics and fundamental freuency
« Last post by revrard on Today at 04:43:54 PM »
Any periodic (or almost periodic) signal is absolutely equivalent to the superposition (the sum) of sine (harmonic is probably more correct) signals called fundamental and harmonics; the fundamental component has the same frequency as the complete signal and the others have frequencies multiple of this one. The harmonic 2 has a frequency double of the fundamental, the harmonic 3, triple, ... The series of fundamental and harmonics is called Fourier series. The web page http://en.wikipedia.org/wiki/Fourier_series gives drawings of interesting examples, though the article is too detailed and mathematical. A practical example is the signal of a relaxation oscillator. A band-pass filter connected to the oscillator and tuned to the fundamental frequency or to one of the harmonics allows to extract the corresponding sine component. Reciprocally, it is possible to reconstruct a complicated periodic signal in summing its harmonic components, using, for example, an op amp adder. However, I doubt that this has many useful application, contrary to the filtering of complex signals.
Electronics chit chat / Re: uses of wavelength
« Last post by revrard on Today at 03:48:58 PM »
Neither the frequency nor the wavelength of a light wave change during propagation in vacuum or in a uniform medium. A beam of light is in general more or less divergent so that its power is spread over a surface increasing with the distance from the source. Therefore, the power falling onto a surface of given area (and the wave intensity, which is the power falling onto a unit surface) decreases with increasing distance, often as 1/the square of this distance. The beam divergence is far lower in lasers than in normal lamps so that they are far less attenuated. This can be observed with lasers used as pointers or in discotheques.
Projects Q/A / Re: 0-30V Stabilized Power Supply
« Last post by thiagoas on Today at 03:32:38 PM »
For those who are interested in this type of project this will be a good series of videos.

Electronic Projects Design/Ideas / Re: Looking to buy pre etched pcb
« Last post by abador on September 13, 2014, 10:31:06 AM »
Hey Hero999, I like your idea. I actually found a module that was about $10 so I decided that one might be better quality so I think I might get that one. I have all the parts in case any of the parts go bad. I'll have to research how to troubleshoot if it doesn't work but I'll tackle that if the time comes. Still would have been cool to build it from scratch but I guess it was a little too advanced for my abilities atm. I'll make sure an ic will fit a perfboard when I conquer my next project. Thanks for the input.

I don't think it does colors though, just black and white (well, grey-scale).  You can get them in huge dimensions and I've never seen one in person so I don't know how it's driven.  I also don't think it's price competitive with lcd technology yet either.  At the large size you're asking about, it might be however.
Datasheet/Parts requests / Cheap alternative to graphic LCD, OLED & TFT displays modules
« Last post by ncgomes on September 12, 2014, 06:35:54 PM »
Seeking a technology or even a manufacturer that could produce graphic display modules, with dimensions between 14'' and 19'', low-res, few colors, but definitely must have white background.

Anyone have any suggestions of manufacturer, or technology, or forum where I can find an answer?

Thank you very much. Best regards, Nuno.
Microelectronics / Re: microeletronics
« Last post by revrard on September 12, 2014, 06:34:37 PM »
You probably mean pic18F4550 (16F4550 doesn't seem to exist). The MPLAB IDE software should enable you to write and compile your programs.
These web addresses should be of some help to you:
Your web browser can also give you more informations.
If you cut the cord and connected a standard mains connector, it would probably work. It wouldn't be safe, since the metal case wouldn't be earthed. The correct way of doing it is to use a three pin plug, witht he eartht conductor connected to the motor's case.
Hello Electronics-Lab people~!
I'm an assemblage artist looking to begin using motion in my art pieces. I recently purchased an old sewing machine motor at a yard sale and would love to get it up and running.

Was wondering if someone had any ideas on how I can wire this bad boy - or get someone to help me. I'm attaching a photo.

The cord is kinda weird, as it has two circular prongs. I don't know what would happen if I spliced the lines to a standard lamp cord.. but I was thinking I might try that to see if the motor would spin. I need a Rheostat on it too.

Am I asking for trouble? Will this cost me an arm and a leg - or burn one off?
Thanks so much for any guidance you can provide,
Shelly Caldlwell
Pickwick & Plum
Datasheet/Parts requests / Re: Breadboard dimensions
« Last post by Boky on September 11, 2014, 04:14:38 AM »
Thank you liquibyte :)
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