Electrical Engineering & Electronics Design

Thank you for your reply Karol,

I am still confused with this but I will read James Maxwell tonight.

It is very hard to understand about the idea of electric field and magnetic field. They are kind of force field, one of the nature’s basic four force fields. We call it electro-magnetic force field. The others are gravitational force field, weak nuclear force field and strong nuclear force field. What these fields can do is that they can exert force on matter. Now the problem is; exert force on what matter?

One always feels the pull of the earth, that is gravitational field and depends on amount of matter which we call mass. That is a macroscopic property.

If you want to peek on to other forces, you need to dive into an atom. There exist particles called electrons, protons and neutrons. Electrons and protons are matter but they have some other peculiar properties. We call it electric charge. We exactly don’t know what charge is, but we know it from their interactions. They can exert force on other charge when they brought close together. This force is 4.1x10 exp 42 times greater than gravitational force. That is why gravitational force can’t do or make any effect when we enter inside atom.

Magnetic field comes solely from electrons. We call it magnetic moment. Why? Because we can not split the origin of magnetic field into to separate portions as we can do it for electric charge. Meaning, magnetic mono-pole does not exist in nature. We cannot separate north pole from south pole. We tried our level best to find it but till now we remain unsuccessful and nature is like that and we can not make argument on that. They co-exist all the time.

Magnets, what we see in our everyday life are ferro-magnets. All materials (macroscopic off course, not at atomic level) in our nature are either ferro-magnetic or paramagnetic or diamagnetic. It depends on the configuration of electrons, mostly at the outer shell. That part is another layer of extensive physics.

The strangest thing about electro-magnetic force field is that a changing electric field spontaneously generates magnetic field and changing magnetic field spontaneously generates electric field.

Static magnetic field can do little except holding plasma in tokamak, static electric field can do a lot. Thunder is the result of static electric field.

When a matter containing charge moves, electric field around its space changes and produces magnetic field. Similarly, when a magnet moves it creates electric field and if any charge is present there it feels a force. In our everyday life, we see these activities as electro magnets where electric current in a coil produces large magnets and generators where magnets are rotated across a coil to produce electricity.

Electromagnetic wave is an entrapped energy stored either in electric or magnetic field of a system, radiated owing to interactions of both. If we consider an atom as an electro-magnetic system, electromagnetic wave is the pathway of exchanging energy from one field to other. As per quantum physics, we call electromagnetic wave as photon. We can pump energy in and out of an atom in terms photon. All the chemistry we see around us is the changes of electric and magnetic field happening inside an atom along with exchange of energy in the form of photons. Here every bits and pieces are dynamic, nothing stays at rest in atomic level.

Thanks Zulfigar.

I will have to keep trying to study this.

The Electric Field is created by charge accumulated over a surface creating a potential difference. Voltage is referenced here.

The Magnetic Field is created by the MOTION of the charge from one source to another. Current is referenced here.

The combination of static charges (voltages) and moving charges (currents) gives the presence of a moving Electro-Magnetic Wave.

Please note that current MUST BE changing in order to create a EM Field.

This is the reason that Alternating Current is used for Radio Frequency as it relates to the FREQUENCY of the changes in current.

Please watch this video to get a complete understanding of the history and how people discovered this phenomenon.

https://www.youtube.com/watch?v=hVu844ZcCdU&t=6s

Thank you Steven. A very good documentary.

This video below explains everything you need to know about your question about the Electric Field.

Magnetic field theory . All magnets have a dipole field with a positive and negative polarity known as north and south.

Electric field theory is different to a magnetic field because the electric field theory only has a negative charge such as the electron or a only a positive charge such as the proton. The field surrounding the electron is not a dipole field like the magnetic field as it only has one polarity negative. It only has a negatively charged field surrounding it.

We can manipulate or drag large numbers of electrons to a storage area such as on a capacitor plate creating a far far more powerful electric field. This is very useful in electronics such as capacitors.

This question is pushing electrical engineering in to the world of physics but is a very good question.

https://www.youtube.com/watch?v=Pd9HY8iLiCA&list=PLyQSN7X0ro2314mKyUiOILaOC2hk6Pc3j&index=3

Jason ; I have watched a few of this particular MIT professors' videos and they are typical of college level course lectures into the math and physical theory, but are not very good in visualization of EM fields. 

The difficulty lies in the presentation is in 2D (blackboards) and the 3D wave fronts are very difficult to present without computer simulation models.

It's unfortunate that the lectures do not include 3D visualizations instead of 2D blackboard explanations. This small difference is a big deal in human comprehension and visualization.

Many of the physical theorists in the late 19th century understood this, but very required to link the mathematical models. Maxwell was the one that almost everyone gives credit to because of the Mathematics relationships , but almost no one understands and / or appreciates that Oliver Heavyside was the one that 'visualized' the Electro-Magnetic waves best especially in the Telegraphers equations :

https://en.wikipedia.org/wiki/Oliver_Heaviside

https://en.wikipedia.org/wiki/Telegrapher%27s_equations

He was also the one to reduce the number of Maxwell equations from 20 to 4

" In 1884 he recast Maxwell's mathematical analysis from its original cumbersome form (they had already been recast as quaternions) to its modern vector terminology, thereby reducing twelve of the original twenty equations in twenty unknowns down to the four differential equations in two unknowns we now know as Maxwell's equations. The four re-formulated Maxwell's equations describe the nature of electric charges (both static and moving), magnetic fields, and the relationship between the two, namely electromagnetic fields."

Hello Steven,

Glad to see you back around in the chat room.

I agree these MIT educational courses could be much improved with 3D simulations models. MIT certainly have the resources and capability to do this. Different people seem to take in and learn new information in different ways such as some people like the mathematics and the equations and some people understand better through visualization like myself. I am not naturally gifted with mathematics although I put in extra effort and find my way through usually. I have had some time off due to hospital so I am currently revising and brushing up on all the basics so I will add Oliver Heavyside to my studies. Anyway really good to hear from you Steven regards Jason

Jason ;

Yes, I have been active again. I created 44 models in 30 days to see what 'badges' that I can get but that game is rigged as I have told you in the past. The current badge I have is for over 100 models and is a recent badge change from 'active uploader' and used to have only 54 awarded people. Now the it has been changed to 'upload master', which is awarded to over 14,000 people, diluting its any real significance. Most of the lower awards and better badges are as 'GrabCAD insiders', so again it is a rigged game, typical of the fake social media 'Likes' Facebook society real world we live in of not 'what-you-know', but 'who-you-know'.

Most of the time I polish my SolidWorks skills with my models and present concepts which I am currently investigating to keep up-to-date on current RF technology trends.

So I will be in and out depending on my project work loads.

Steven

Wow thank you so so so much Jason. I have been trying to find the answer to this for ages.

Thanks!

The way you described electricity and magnetism is the application part. This application part can be exploited best if the manifestations comes from studying Physics. Its always the Physics first then Engineering and never other way around.