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blog:2019-10-21:conceptual_electronics_videos [2019/10/21 09:41] ve7hzfhowto:conceptual_electronics_videos [2020/11/01 16:15] (current) – old revision restored (2020/10/31 23:32) va7fi
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 +~~NOTOC~~
 ====== Conceptual Electronics Videos ====== ====== Conceptual Electronics Videos ======
  
-I just found a series of videos that animate various physics concepts.  The first one I found was on the concept of impedance: +This [[https://www.youtube.com/playlist?list=PLkyBCj4JhHt9dIWsO7GaTU149BkIFbo5y |series of 24 videos]] manages to start from scratch and work its way up to Electromagnetism pretty much without math.  One thing they could have improved though is the labelling.  So while you watch the videos, keep in mind that:
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-{{ youtube>zO7RZZW0wSQ }} +
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-But this was #15 in a [[https://www.youtube.com/playlist?list=PLkyBCj4JhHt9dIWsO7GaTU149BkIFbo5y |series of 24 videos]].  I just finished watching the first few and they basically managed to start from scratch and work their way up to Electro-Magnetism Pretty cool!  One thing they could have improved is the labelling:+
   * Red particles are <fc #ff0000>positive</fc> charges   * Red particles are <fc #ff0000>positive</fc> charges
   * Blue particles are <fc #4682b4>negative</fc> charges   * Blue particles are <fc #4682b4>negative</fc> charges
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   * Green arrows are <fc #008000>magnetic</fc> fields.   * Green arrows are <fc #008000>magnetic</fc> fields.
  
-Alsothis first video can seem overwhelmingwith all these fields creating each other, but there'really only four rules:+I would probably also skip the second videowhich I found a bit long and abstract.  Here's a quick summary of it: 
 + 
 +  * [4:00] Magnetic fields exerts a force on moving charged particles because a moving charged particle creates curly magnetic field around it (Ampere's Law) so the particle behaves like a magnet.  This is the principle behind old Cathode Ray Tube TVs: send electrons flying toward a screen that can image them, and adjust their deflection using a magnetic field. 
 +  * [4:16] A charged particle moving in a loop creates a magnetic field (Ampere's Law) which is the same for a spinning electric charge, which is the what permanent magnets are made of.  Notice how the magnetic field lines form closed loops (Gauss' Law of Magnetism). 
 +  * [5:20] Magnetic fields can be created by a current through a wire (first part of Ampere's Law), which is how electric motors function. 
 +  * [7:08] Electric fields can be created by a magnetic field which is changing in time (Faraday's Law of Induction)which is how alternators function. 
 +  * [10:15] Magnetic fields can also be created by a changing electric field (second part of ampere's law).  Together with the other three laws, these can lead to a feed back loop where a changing magnetic field creates a changing electric field, which creates a changing magnetic field, and so on.  This is how electromagnetic waves are created. 
 + 
 +In mathematical terms, there are four equations (known as [[wp>Maxwell's_equations#Formulation_in_SI_units_convention |Maxwell'Equations]]) that explain all the electromagnetic phenomena we observe:
  
 |<100% - 17em - >| |<100% - 17em - >|
-^Name        ^Math ^Description | +^Name        ^  Math  ^Description ^Pictures 
-|Gauss' Law  |  $$\vec{\nabla} \cdot \vec{E} = \frac{\rho}{\varepsilon_0}$$  | An electric charge (right) creates an electric field that points away from the charge and "disperses" to infinity (left)+|Gauss' Law  |  \$$\vec{\nabla} \cdot \vec{E} = \frac{\rho}{\varepsilon_0}\$$  |An <fc #ff0000>electric charge, \$\rho\$</fc>, creates an <fc #9400d3>electric field, \$\vec{E}\$</fc>, that points away from the charge and "disperses" to infinity|{{:howto:maxwell1.png?200}}
-|Gauss' Law of Magnetism |  $$\vec{\nabla} \cdot \vec{B} = 0$$  | A magnetic field (left) can not "disperse" to infinity the way an electric field can.  In other words: "magnetic charges" don't exist the way electric charges do. | +|Gauss' Law of Magnetism |  \$$\vec{\nabla} \cdot \vec{B} = 0\$$  | A <fc #008000>magnetic field, \$\vec{B}\$</fc>, can not "disperse" to infinity the way an electric field can.  Instead, magnetic field lines loop onto themselves.  In other words: "magnetic charges" don't exist the way electric charges do. |{{:howto:maxwell2.png?200}}
-|Faraday's Law of Induction |  $$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}$$  |A changing magnetic field (right) creates a "curly" electric field (left) and vice-versa. | +|Faraday's Law of Induction |  \$$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}\$$  |A <fc #008000>changing magnetic field, \$\vec{B}\$</fc>,  creates a <fc #9400d3>"curly" electric field, \$\vec{E}\$</fc> and vice-versa. |{{:howto:maxwell3.png?200}}
-|Ampere's Law|  $$\vec{\nabla} \times \vec{B} = \mu_0 \Big(\vec{J} + \varepsilon_0 \frac{\partial \vec{E}}{\partial t} \Big)$$  |An electric current and/or a changing electric field (right) creates a "curly" magnetic field (left) |+|Ampere's Law|  \$$\vec{\nabla} \times \vec{B} = \mu_0 \Big(\vec{J} + \varepsilon_0 \frac{\partial \vec{E}}{\partial t} \Big)\$$  |An <fc #ff0000>electric current, \$\vec{J}\$</fc>, and/or a <fc #9400d3>changing electric field, \$\vec{E}\$</fc>, creates a <fc #008000>"curly" magnetic field, \$\vec{B}\$</fc>|{{:howto:maxwell4.png?200}}| 
  
-Together, these four equations (known as [[wp>Maxwell's_equations#Formulation_in_SI_units_convention |Maxwell's Equations]]) account for all the electromagnetic phenomena we observe: 
-  *  
  
howto/conceptual_electronics_videos.1571676089.txt.gz · Last modified: 2019/10/21 09:41 by ve7hzf