snearch + elektrotechnik   29

Kirchhoff’s Voltage Law versus Faraday’s Law: the Conclusion - YouTube
Dries van Oosten
vor 1 Monat
The whole discussion boils down to your statement around 8:24, when you say voltage is any energy divided by charge. When a physicist uses the term voltage, he/she refers to an electric potential difference. And an electric potential difference is a potential energy difference, divided by charge. And you cannot define a unique potential energy in the presence of a time dependent magnetic field. This exactly demonstrated by the fact that that loop integral is nonzero. A potential energy should only depend on position and not on how you got to that position.

You use a more general definition of voltage, by dividing energy by charge and leaving out the word potential. So you essentially say that the electric potential is the total energy divided by the charge.

As a physicist I don't think that is correct and I consider the emf as an electric potential, even it can do some of the same stuff an electric potential can and has the same unit.

Now, why do we care so much about this distinction and why should you not? Because for an electrical engineer, your working definition of voltage doesn't get you in trouble, because you know what you are doing and you are trained to avoid the dangers of abusing of the concept of a potential (dangers that Lewin runs straight into with his faulty probing). So, within the framework of electrical engineering, you are correct. Why should a physicist care? Because you definition of voltage is not formally equivalent to a potential difference, but you use it as such. Does that matter to you? Ofcourse not. Why should it? We physicists are strange people.
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Lernherausforderung  Lewin_Walter  Physik  Elektrotechnik  Kirchhoff's_Law  Faraday's_Law  EMF  ElectroBOOM 
january 2019 by snearch
Bringing up 802.11ac on FreeBSD | Hacker News
I used to work with wireless driver guys. Some of them had no degrees (including one who worked at Lucent on Apple's Airport). Just started out doing small stuff and worked their way up. Others had EE backgrounds. One of the things about wireless is that the salient concepts are more EE than CS, even if you're on the software side. A specialized EE course on wireless communications will teach you a lot of the underlying concepts you need to understand.

sohkamyung 9 hours ago [-]

Yes, it's learning on the job.
In the specific case of 802.11 (different from 'Wi-Fi' which is a marketing term from the Wi-Fi consortium), you'll also need to be familiar with the IEEE 802.11 specifications. You can do this by putting aside a block of time to read parts of the actual specs [1], supplemented by the O'Reilly 802.11 books by Matthew Gast [2] which I found to be really helpful during my time working with various 802.11 modules.
[1] [ http://standards.ieee.org/about/get/802/802.11.html ]
[2] [ http://www.oreilly.com/pub/au/692 ]
reply
System_Programming  WiFi  wireless  802.11  FreeBSD  Linux  Elektrotechnik  Hintergründe  TOP  Inspiration 
may 2017 by snearch
Tesla-Schreck – Elektro-Porsche mit 600 PS und 500 km Reichweite
Antrieb mit Rekuperation

Der Antrieb des Mission E ist völlig neu. Zwei permanent-erregte Synchronmotoren beschleunigen den Sportwagen und gewinnen beim Bremsen Energie zurück. Zusammen leisten sie über 440 kW, katapultieren den Mission E in weniger als 3,5 s auf Tempo 100 und in unter 12 s auf 200 km/h.
PKW  Elektromobilität  Porsche  Mission_E  Feinwerktechnik  Ingenieur  800-Volt-Technik  Elektrotechnik  Synchronmotor  Torque_Vectoring  Lithium-Ionen  Technologie  Akkumulator 
september 2015 by snearch
Maxwell’s Unification Revolution — Starts With A Bang! — Medium
Einstein, who was born in 1879, the year that Maxwell died, often acknowledged a debt to the Scottish physicist. As he once wrote:

We may say that, before Maxwell, Physical Reality, in so far as it was to represent the process of nature, was thought of as consisting in material particles, whose variations consist only in movements governed by partial differential equations. Since Maxwell’s time, Physical Reality has been thought of as represented by continuous fields, governed by partial differential equations, and not capable of any mechanical interpretation. This change in the conception of Reality is the most profound and the most fruitful that physics has experienced since the time of Newton.
Wissenschaftler  Maxwell_James_Clerk  model  Elektrotechnik  Einstein_Albert  citations 
september 2015 by snearch
Schutzleiter – Wikipedia
Ein ganz anderer Themenkreis ist die Farbgebung der Leitungen, die bis 1965 national sehr individuell war und nach diversen Quellen eine rote Farbkennzeichnung für den Schutzleiter in den Ländern Deutschland, Österreich, Schweiz (und anderen Ländern) vorsah.[4] Dabei ist zu beachten, dass die rote Farbkennzeichnung nicht ausschließlich dem Schutzleiter alleine vorbehalten war. Ein rot gekennzeichneter Leiter konnte auch ein geschalteter Außenleiter oder L2 im Dreileiter-Wechselstromnetz, nicht aber der PEN sein.
Lernherausforderung  teuer_bezahlt  Farbe  Schutzleiter  rot  Farbgebung_der_Leitungen  Elektrotechnik  Elektroinstallation  PE-Leiter 
august 2015 by snearch
Bürokauffrau studiert ohne Abitur an einer Uni - SPIEGEL ONLINE
Zurzeit bewerbe ich mich bei Unternehmen. Die Aussicht auf spannende Jobs ist ein toller Lohn für die harte Arbeit.
TOP  Inspiration  Berufswahl  Elektrotechnik 
june 2015 by snearch
msarnoff.org - Terminalscope Serial Console
A great thing about the Terminalscope is its simplicity. Other scope projects require an expensive DAC or an inaccurate R-2R ladder. Rather than draw each character with individual strokes, op-amps are used to generate a raster scan across the screen (like a TV) and the Z axis (beam intensity) is modulated directly by the microcontroller.
CoolStuff  Shell  Hardware_Basteleien  DIY  Linux  Oszilloskop  Elektrotechnik  Terminalscope 
february 2010 by snearch
U. of Arizona student builds Ubuntu-Atom powered spider-bot - Neoseeker News Article
Matt Bunting, a electrical engineering student at the University of Arizona, has been attracting some attention with his latest creation: a six-legged robot that he built for a class on cognitive robotics.
Elektrotechnik  AI  Hardware_Basteleien  Embedded_Systems  funny  video  Hexapod  robot 
february 2010 by snearch

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