Electrodynamics

Course Level 2
Elektrisches Feld (Feldlinien) - zwei entgegengesetzte Ladungen (Dipol)

Here you will learn the basics of electromagnetism. Interaction between electric charges and the effect of the magnetic field.

Lesson Level 3

The 4 Maxwell's Equations in Vacuum

Elektrischer Fluss - Skalarprodukt von Flächenorthogonalvektor und E-Feld

Simple explanation of the Maxwell's equations for beginners. The divergence integral and the curl integral theorems are also explained.

Lesson Level 2

Ohm's law: Formula, Graph and 3 Easy Examples

Ohmsches Gesetz - linearer Zusammenhang zwischen Strom und Spannung

Here you learn Ohm's law, how it is expressed as a formula and as a graph. We also look at three examples.

Lesson Level 1

Voltage explained simply

Voltage between minus and plus pole

Here you will learn what voltage is, how it is generated by charge separation, how a voltage source can be created, and what voltage has to do with current.

Videos

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Video Level 2

Ohm's law explained simply in 13 minutes!

Ohm-law

Here you will learn how to recognize Ohm's Law in a U-I diagram and how to apply the associated URI formula. Three examples are covered.

Content of the video
  1. [00:00] Hello there!
  2. [00:44] The 1st ingredient: Voltage
  3. [01:30] The 2nd ingredient: Electrical conductor
  4. [01:57] The 3rd ingredient: Electric current
  5. [03:28] Data points and Ohm's law as a graph
  6. [05:58] Ohmic conductors
  7. [06:44] Slope of the graph
  8. [07:52] Ohm's law as a formula
  9. [10:10] Electrical resistance
  10. [10:16] Example #1: Resistance unknown
  11. [10:42] Example #2: Voltage unknown
  12. [11:10] Example #3: Current unknown
Video Level 1

Voltage explained simply in 10 minutes!

Voltage

Here you will learn what voltage is, how it is generated by charge separation, how a voltage source can be created, and what voltage has to do with current.

Content of the video
  1. [00:00​] Hello there!
  2. [00:48​] Positive and negative electric charge
  3. [02:00​] Charge separation generates voltage
  4. [03:46​] Voltage is energy per charge
  5. [06:21​] Voltage source and electric current
  6. [08:57] Is voltage dangerous?
Video Level 1

Electric Current explained simply in 7 minutes!

Electric Current

In this video you will learn the basics of the electric current, i.e. the definition, its physical meaning and unit.⠀

Content of the video
  1. ⏲ [00:25] Electric charges
  2. ⏲ [02:11] What causes the electric current?
  3. ⏲ [03:42] Formula + unit of electric current
  4. ⏲ [05:43] Is one ampere a large current?
  5. ⏲ [06:44] Summary
Video Level 3

Maxwells Equations explained extensively in 40 minutes!

Maxwell equations

The Maxwell’s equations are studied in the second semester of physics. Here you will learn EVERYTHING about them just within 40 minutes - explained for BEGINNERS!

Content of the video
  1. ⏲ [00:14] Applications of the Maxwell equations
  2. ⏲ [02:08] Electric field vector
  3. ⏲ [05:12] Magnetic field vector
  4. ⏲ [10:15] Divergence integral theorem - this mathematical theorem combines the volume integral of the divergence of a vector field with the surface integral of this vector field.
  5. ⏲ [10:15] Divergence integral theorem - this mathematical theorem combines the volume integral of the divergence of a vector field with the surface integral of this vector field.
  6. ⏲ [17:50] Curl integral theorem - this mathematical theorem combines the surface integral of the curl of a vector field with the line integral of this vector field.
  7. ⏲ [23:58] The FIRST Maxwell’s equation - states that the charges are sources and sinks of the electric field.
  8. ⏲ [27:46] The SECOND Maxwell’s equation - states that magnetic charges always occur as dipoles. There are no magnetic monopoles.
  9. ⏲ [30:23] The THIRD Maxwell’ equation (Faraday’s law of induction) - states that a time-varying magnetic field generates an electric field and vice versa. This Maxwell equation contain also the Lenz’s rule.
  10. ⏲ [35:02] THE FOURTH Maxwell’s equation - states that the magnetic field can be generated by electric currents and time-varying electric fields (displacement current)
Video Level 2

Plate Capacitor explained simply in 7 minutes!

Plate capacitor

Here the plate capacitor is simply explained. With the help of the capacitor you will learn about the electric voltage, electric field and electric capacitance and how to calculate them for a plate capacitor.

Content of the video
  1. ⏲ [00:11] Setup and Applications of a plate capacitor
  2. ⏲ [01:58] Voltage
  3. ⏲ [03:38] Capacitance
  4. ⏲ [04:57] Force on a test charge & Electric field

Questions

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Question Why can't electric field lines cross?

Illustrations

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Two coils connected in parallel
Two coils connected in parallel
Two coils connected in series
Two coils connected in series
Crossing field lines - ambiguous force direction
Crossing field lines - ambiguous force direction
Electric field lines - force on a test charge
Electric field lines - force on a test charge
Electromagnetic wave (EM wave)
Electromagnetic wave (EM wave)
RL circuit - Switch-on process
Resistor in series with a coil (RL circuit) - Switch-on process
Different resistances - different slopes (U-I characteristics)
Different resistances - different slopes (U-I characteristics)
Ohmic conductor vs. non-ohmic conductor (U-I characteristics)
Ohmic conductor vs. non-ohmic conductor (U-I characteristics)
Ohm's law - linear relationship between current and voltage
Ohm's law - linear relationship between current and voltage
Voltage drop between negative and positive poles
Voltage drop between negative and positive poles
Relationship between voltage and kinetic energy
Relationship between voltage and kinetic energy
Relationship between voltage and kinetic energy
Relationship between voltage and kinetic energy
Electric dipole in inhomogeneous electric field
Electric dipole in inhomogeneous electric field
Electric Field Graph (inside / outside) - Hollow cylinder
Electric Field Graph (inside / outside) - Hollow cylinder
Electric Potential Graph (inside / outside) - Hollow sphere
Electric Potential Graph (inside / outside) - Hollow sphere
Faraday cage and electric field
Faraday cage and electric field
Electric Potential Graph (inside / outside) - Solid sphere
Electric Potential Graph (inside / outside) - Solid sphere
Electric current between plus and minus pole
Electric current through a cross-sectional area
Elektrisch positive / negative Ladung - Anziehung und Abstoßung
Electric positive / negative charge - attraction and repulsion
Elektrische Kraft auf eine Ladung im Plattenkondensator
Electric force on a charge in a plate capacitor