WIlliam Ketel's profile
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- Skin effect
- This descriptive posting shows a very practical aspect of understanding the skin effect. So all of those heavy plated RF coils carried the current in the plating, and the rest of the copper served to dissipate the heat. Very interesting. Now I am wondering about the RF coils I see for some fairly high frequencies and the coils are supposed to be #30 copper wire, enamled, not plated. The equivalent resistance must be quite high, which must certainly have a negative effect on the selectivity of tuned circuits. I wonder if those designers understand any of this.
- Just winging it!
- Quite a change from what we normally see, and the best part is NO ARDUINO PROCESSOR to do the blinking. I would have anticipated a different method of connection, but only because I am more familiar with it. And far better instructions than most gadget freak projects.
- True or false? High-power LEDs don’t generate IR heat in the forward direction like a filament lamp
- The fact is that almost always, when you have radiated energy absorbed, you have a temperature rise, which leads to the radiation of heat energy, most often as infrared radiation. This is not new, it is just appearing where it was not expected.
- Toward bendable electronics
- We have had bendable electronics in the form of flexible circuits for quite a while. So this must be quite different to provide any greater value. Printing conductors on flexible plastics may provide just such additional value, but it may be that it is not cost effective, either because of a short lifetime, because of poor reliability, or because of the resistance being to high for a lot of applications. But if the quality is adequate then probably the first area will be in medical devices, followed by use in toys of various kinds.
- Tips & Tricks: Keep pace with LED advances using reference designs
- an Interesting posting, and the part about not replicating the omnidirectional radiation of the old A19 bulb. But there is a fault in the assumption that everybody would choose to replicate that radiation pattern, which was common because any other pattern cost more to produce. I would really prefer to have some choices in the radiation pattern, instead of being locked into that selected by the "we always did it that way before" mindset. The point source radiating in all directions is not the most efficient for a whole lot of applications, including most of my applications. A hemispherical pattern would be better for some general lighting applications, even for many applications that used a reflector. And a fairly narrow cone, or even a beam, would be useful for others. So drop the fear factor and put some other radiance patterns on the shelves.
- VCO using the TL431 reference
- An interesting and educational article, this one. Previously my efforts have been toward preventing any oscillations of voltage regulators and references, rather than using them. So the whole concept is interesting from that point of view as well.
- Ultrasonic shoe sensors help the visually impaired
- Quite an interesting concept here, but sensors on the edge of a shoe would not last an hour for most folks. Mounted a small bit higher and looking downward just a small bit would work much better. And use a flexible piezoelectric transducer under the foot to avoid the cables goingup into a pocket vibrator. That woul put thesensing near the detector, which would be far more intuitive in this instance. And lose that Ardino processor, for goodness sake. The whole thing can function very well withoutthat power hog pulling down the batteries.
- Bach for Engineers
- I suppose that Bach pieces played by an adequately skilled orchestra could enhance one's workday and potentially improve one's performance. I have never had that luxury, the very worst of the music being either bad jazz played through six-inch horn speakers, or else that awful stuff marketed as "beautiful music", because it contains violins, played by people with very little skill and much less talent, for example, Andre Kastelantz, and also the 101 strings. Two groups able to produce incredibly bad music even without hitting any wrong notes.
- Connector voltage stress, Part 2
- The device is close to the recommended value, and if the portion of the threaded area behind the panel was given a coat of insulating thread locker after installation the leakage path would exceed one inch. So there is a simpl way to comply with the standard.