Intelligence agency by Ciro Santilli 37 Updated +Created
English idiom by Ciro Santilli 37 Updated +Created
Oscilloscope by Ciro Santilli 37 Updated +Created
Video 1.
FNIRSI 1014D review by Kerry Wong (2022)
Source. One of the cheapest oscilloscopes available at the time.
Maxwell's equations by Ciro Santilli 37 Updated +Created
Unified all previous electro-magnetism theories into one equation.
Explains the propagation of light as a wave, and matches the previously known relationship between the speed of light and electromagnetic constants.
The equations are a limit case of the more complete quantum electrodynamics, and unlike that more general theory account for the quantization of photon.
The system consists of 6 unknown functions that map 4 variables: time t and the x, y and z positions in space, to a real number:
  • , , : directions of the electric field
  • , , : directions of the magnetic field
and two known input functions:
  • : density of charges in space
  • : current vector in space. This represents the strength of moving charges in space.
Due to the conservation of charge however, those input functions have the following restriction:
Equation 1.
Charge conservation
.
Also consider the following cases:
  • if a spherical charge is moving, then this of course means that is changing with time, and at the same time that a current exists
  • in an ideal infinite cylindrical wire however, we can have constant in the wire, but there can still be a current because those charges are moving
    Such infinite cylindrical wire is of course an ideal case, but one which is a good approximation to the huge number of electrons that travel in a actual wire.
The goal of finding and is that those fields allow us to determine the force that gets applied to a charge via the Equation "Lorentz force", and then to find the force we just need to integrate over the entire body.
Finally, now that we have defined all terms involved in the Maxwell equations, let's see the equations:
Equation 2.
Gauss' law
.
Equation 3.
Gauss's law for magnetism
.
Equation 4.
Faraday's law
.
Equation 5.
Ampere's circuital law
.
You should also review the intuitive interpretation of divergence and curl.
Pin header by Ciro Santilli 37 Updated +Created
These often come pre-soldered on devboards, e.g. and allow for easy access to GPIO pins. E.g. they're present on the Raspberry Pi 2.
Why would someone ever sell a devboard without them pre-soldered!
Figure 2.
Underside of a Raspberry Pi 2
. Source. At the top of this image we can clearly see how the usually pre-soldered pin header connectors go through the PCB and are soldered on both sides.
Weston cell by Ciro Santilli 37 Updated +Created
Covariance and contravariance of vectors by Ciro Santilli 37 Updated +Created
Eigenvector by Ciro Santilli 37 Updated +Created
Directed graph by Ciro Santilli 37 Updated +Created
Digital Light Processing by Ciro Santilli 37 Updated +Created
Direct democracy by Ciro Santilli 37 Updated +Created
Fraud by Ciro Santilli 37 Updated +Created
Ultra-high-energy cosmic ray by Ciro Santilli 37 Updated +Created
Sometimes it feels like this could be how we finally make experiments to see what the theory of everything looks like, a bit like the first high energy experiments were from less exotic cosmic rays.
Local symmetry by Ciro Santilli 37 Updated +Created
Appears to be a synonym for: gauge symmetry.
A local symmetry is a transformation that you apply a different transformation for each point, instead of a single transformation for every point.
TODO what's the point of a local symmetry?
Bibliography:
Inclusionism by Ciro Santilli 37 Updated +Created
Closurism by Ciro Santilli 37 Updated +Created
Closurism is a term invented by Ciro Santilli to refer to content moderation policies that lock threads in online forums, preventing people from adding new comments from that point onward.
This is similar to deletionism but a bit less worse, as the pre-existing content is maintained. But new relevant content that comes up cannot be added in the future, so it is still bad.
The outcome of closurism is that new forum posts must then be made about up-to-date aspects of the topic. But then those may fail to reach the same PageRank, so most people never get the new information, or create new posts leading to useless duplication of work.
Deterministic game by Ciro Santilli 37 Updated +Created

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