# Basic electronics theory (response to Layman's issues)

Discussion in 'Architecture & Engineering' started by billvon, Nov 18, 2014.

1. ### TrippyALEA IACTA ESTStaff Member

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No, he's demonstrating the electrostatic field, not the magnetic field.

Yes, they're related, they're both mediated by virtual photons, for example, however, you can have an electric field without a magnetic one, and a magnetic field without an electric one. The unification of electric and magnetic fields (among other things) explains why moving charges can generate magnetic fields, and why magnetic fields can influence moving charges.

3. ### LaymanTotally Internally ReflectedValued Senior Member

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http://en.wikipedia.org/wiki/Electromagnetic_field

"An electromagnetic field (also EMF or EM field) is a physical field produced by electrically charged objects."

"The field can be viewed as the combination of an electric field and a magnetic field."

"Discrete structure

The electromagnetic field may be thought of in a more 'coarse' way. Experiments reveal that in some circumstances electromagnetic energy transfer is better described as being carried in the form of packets called quanta (in this case, photons) with a fixed frequency. Planck's relation links the energy E of a photon to its frequency ν through the equation:[1]

where h is Planck's constant, named in honor of Max Planck, and ν is the frequency of the photon . Although modern quantum optics tells us that there also is a semi-classical explanation of the photoelectric effect—the emission of electrons from metallic surfaces subjected toelectromagnetic radiation—the photon was historically (although not strictly necessarily) used to explain certain observations. It is found that increasing the intensity of the incident radiation (so long as one remains in the linear regime) increases only the number of electrons ejected, and has almost no effect on the energy distribution of their ejection. Only the frequency of the radiation is relevant to the energy of the ejected electrons.

This quantum picture of the electromagnetic field (which treats it as analogous to harmonic oscillators) has proved very successful, giving rise to quantum electrodynamics, a quantum field theory describing the interaction of electromagnetic radiation with charged matter. It also gives rise to quantum optics, which is different from quantum electrodynamics in that the matter itself is modelled using quantum mechanics rather than quantum field theory."

5. ### Aqueous Idflat Earth skepticValued Senior Member

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Lol. Now we only need to decide if this is an "instance" of Dunning-Kruger or one of its many "moments".

My point exactly. The electric polarity you referred to (loosely giving us the Bohr model of an ion) is completely different than the magnetic moment, which is due to the motion of the captive electron (simplified model).

Remember: the magnetic field only arises from motion of charged particles. The capacitor exploits electrostatics, which (except for the inductance in the leads and current across the dielectric) is the opposite of "charge in motion".

Lol. Nth moment of Dunning Kruger.

7. ### TrippyALEA IACTA ESTStaff Member

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Yes, the electromagnetic field can be viewed as a combination of electric and magnetic fields, however, none of this changes the fact that a stationary electric charge produces an electric field without a magnetic one, which is the original assertion you made.

8. ### LaymanTotally Internally ReflectedValued Senior Member

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Okay, then if the magnetic field is described by the exchange of a virtual photon, and the electrostatic field is created by the exchange of a virtual photon, then the actual force between the two objects is generated by the same thing. The only difference I see here is that the electrostatic field doesn't involve current and the magnetic field does, but current could still flow from an electrostatic field, like through a capacitor or linked to a voltage divider.

9. ### LaymanTotally Internally ReflectedValued Senior Member

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The cause of the actual force is the same basic interaction.

10. ### LaymanTotally Internally ReflectedValued Senior Member

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They would both produce the same force! I don't see any relevance to the distinction here. A magnetic and electrostatic field would both do the same job of attracting on object to another.

11. ### LaymanTotally Internally ReflectedValued Senior Member

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It is even said that a photon has a magnetic and electric field that are 90 degrees from each other. Then if the electrostatic field was produced by an exchange of photons, then that photon would possess a magnetic field.

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Lol.

13. ### Aqueous Idflat Earth skepticValued Senior Member

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For the umpteenth time: magnetism is induced by the motion of charge. Do not confuse this with the photon, which is a quantum of radiation, and carries the energy conferred to it as a wavelet of EMR.

14. ### TrippyALEA IACTA ESTStaff Member

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They are related, but they are in essence, different aspects of the same thing.

A changing magnetic field creates an electric field, but a static magnetic field does not.
A changing electric field creates a magnetic field, but a static electric field does not.

You can create one using the other, but the presence of one does not neccessarily imply the presence of both.

This is why we have two different components, inductors and capcitors, both of which behave differently.

Inductors store electrical energy as a magnetic field. They, as I recall, behave as having very high impedance while 'charging' and then act as a short circuit once charged.
Capacitors store electrical energy as a magnetic field. They behave as a short circuit while charging, and once charged behave as an open circuit.

Both components exhibit varying resistance as the charge and discharge. You can even connect a resistor, capacitor, and an inductor in a loop with a switched DC power supply in paralell to the inductor, and once the switch is open the RLC circuit will resonate producing an AC voltage and current that will decay over a period of time as power is consumed by the resistance of the various components.

Here's a Java based simulation of such a circuit: link

15. ### leopoldValued Senior Member

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didn't you know?
the flux capacitor makes use of the rotating field.
that dude from back to the future told me.

a capacitor that uses a rotating field, where do you come up with this stuff layman?

16. ### LaymanTotally Internally ReflectedValued Senior Member

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I guess the point I am trying to make here is that the attractive force created by a magnetic field is the same as the attractive force created by an electrostatic field, and that is why I have read so many times that they are two aspects of the same thing. If it makes you happy, I could use the correct term to denote what the source is, but that doesn't change the fact that an electrostatic field is felt as an attractive force. That is why I really didn't see any difference between the two.

17. ### TrippyALEA IACTA ESTStaff Member

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If you take a piece of amber, charge the shit out of it with a piece of silk, it will be no more attracted to a permanent magnet than it was before you charged it.

18. ### LaymanTotally Internally ReflectedValued Senior Member

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Then wouldn't two dielectric plates feel an attractive force? Then wouldn't two inductors flowing with current also experience an attractive force? The way you guys made it sound before is as though two dielectric plates would not attract each other; a balloon rubbed on ones head wouldn't stick to their hair.

19. ### Aqueous Idflat Earth skepticValued Senior Member

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No, the electrostatic force is one thing, and magnetostatic force, which arises from electrodynamics, is separate. You are equating charge and spin, or charge and current, which is incorrect. Also note, the force does not exist, but rather the force field. Force can only be developed, by interaction of particles with fields.

20. ### Aqueous Idflat Earth skepticValued Senior Member

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You are referring here to the electrostatic force.

The two inductors, as long as they are not orthogonal, and as long as some current passes through them concurrently, will develop a mutual force. This is exactly how some motors work. This is the magnetic force, not the electric force.

Last edited: Nov 23, 2014

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Lol.

22. ### TrippyALEA IACTA ESTStaff Member

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Correct, an attractive force exists between the plates of a capacitor, it is an electrostatic force, but it has no magnetic component.

They might, or they might experience a repulsive one, depending on the orientations of their coils with respect to each other.

No, nothing anyone has said has even remotely implied that, in fact, this assertion has been contradicted multiple times.

If you're struggling with this stuff, then this video is really going to blow your mind: URL

Copper is not magnetic, it's not attracted to the copper pipe. However, when you drop the magnet through the copper pipe, the magnet accelerates, this motion causes eddy currents to be set up in the copper pipe, which cause their own magnetic fields, which oppose those of the bar magnet, braking it and slowing its motion.

23. ### LaymanTotally Internally ReflectedValued Senior Member

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Well fine then, if it is the electrostatic force than I guess I have to say it is that force that creates the attractive force from the electromagnetic force. The point is, it still would create the same attractive force from the electromagnetic force as would the magnetic force.