Displacement current, where is it in electronics?

[lordvader88]

Although I have done some stuff with the differential form of Maxwell's eq's and with Clifford algebra, I never did enough to understand what the displacement current is (I just did it for fun on my own, not in class with problems/applications/tests)

So where/when does it show up in EE courses, dealing with resistors, capacitors, inductors, and semi-conductors?


I do have utube, but I'm asking anyways

[Wimberleytech]

I watched the video.  It should answer you question very well.

Displacement current is the current that charges a capacitor.

It shows up in EE everywhere capacitors are discussed (which includes semiconductors).  It may be called "charging current" instead of "displacement current."

[rfeecs]

So where/when does it show up in EE courses, dealing with resistors, capacitors, inductors, and semi-conductors?

Pretty much nowhere.  Although sometimes it is mentioned in dealing with capacitors, it is not needed to understand or describe how a capacitor works.  It might be mentioned in a discussion of how to apply Kirchhoff's law to one plate of a capacitor or something obscure like that.

Where it is mentioned is when you have propagating electromagnetic fields:  in antennas, transmission lines, waveguides.

Maxwell added a term to Ampere's law:
Ampere's law says that a current produces a magnetic field.  The term Maxwell added is the displacement current.  It says that a changing electric field also acts like a current and also produces a magnetic field.

Now, Faraday's law says that a changing magnetic field produces an electric field;  the displacement current addition says that a changing electric field produces a magnetic field.  So the two coupled fields can create an electromagnetic wave that can propagate through space.  This can only be explained by adding the displacement current to Ampere's law.