*** Electrophorus ***

[baroutologos]

how i missed to know what electrophorus is some 5 years ago?


**
PART 1


I was seeing one youtube vid showing how electrophorus works and i read some wikipedia also. How a simple thing like that teaches you the fundamental behaviour of charges.


A charged non conducting surface, when in touch with a conducting metal plate, makes the conducting plate expel or attracts electrons from a charge reservoir aka ground with a zap, and reaches equilibrium. When grounding is removed and the metal plate is parted from the charged non conductive surface, then it develops, again, a charge -leaving the plate electrified - that charge can be returned to the ground reservoir with a reversed zap. zap-zap

Can be done numerous times without applying any electricity, battery, friction etc. Just from a static field.


**


after my initial amazement from the trivial for others fact, my mind start wondering..


1) Will electroforus work (instead of a charged non conductor)
with an isolated electrified metal plate that has a non conducting surface (e.g. from teflon) hence plate A
and a second typical metal plate B that will come into contact? (teflon separated)


yes or not?


2) What about... having the same charged plate A, isolated with teflon both sides and bringing into contact two metal plates like B each side. will "energize" them  both equaly?
yes or not?




PART 2




Further more i was seeing makeshift polarity electrostatic detectors to prove the experiments. Now i was pondering... how is different a capacitor's plate that "holds a charge" from an isolated charged metal plate.


Obviously, a charged / electrified single metal plate can zap a ground. On the other hand, a charged capacitor plate cannot zap a ground. Instead the charges inside a two-plate capacitor are interacting, being "trapped" together
and no unilateral charge movement can be made.


BUT still, We regard that in the parallel capacitor model, the possitive plate has an excess of possitive charges and the negative plate has an excess of negative charges.
We depict the capacitor plates with the - and + signs and we draw the electric field lines between them.


Is there any actual electric field emanating from parallel capacitor plates outwards??




The HYpothesis


Imagine we have a 3 plate capacitor. Just 3 parallel plates isolated between them in a sandwich mode. What if we apply voltage to the first two ones.That is first from left a - polarity, mid plate a + polarity, third not connected.
How the developed field interacts on the third plate?


Do the first two capacitor plates behave as an electrophorus? Does the electric field developed by the two first plates interacts with the third plate?
Will charge movement result from ground reservoir to the third plate? As a responce of the electric field developed by the mid (+) plate?


According my gut, is that will never happen. But yet cannot see why.


Please for conversation's shake enlighten me.


Thanks
Baroutologos

[baroutologos]

Ok.. this vid was created excactly for people like me. 


https://www.youtube.com/watch?v=E9Wrq8ehEvs


It clearly (and theroretically shows) that e-field in a parallel plate capacitor is existant only between plates and cancels after each plate.
Clearly again, the Electrostatic field forces do NOT start from possitive charges and terminate on negative charges forming a dipole, no matter how furtehr apart the charges are,, rather each field exists on its own and occasionaly add or mutualy cancel.


This is in stark contrast to magnetic field that forms dipoles, and many little magnets can be stucked in a row.

[conradelektro]

1) Will electroforus work (instead of a charged non conductor)
with an isolated electrified metal plate that has a non conducting surface (e.g. from teflon) hence plate A
and a second typical metal plate B that will come into contact? (teflon separated)

I made three videos showing just that. Yes, it works, and one can make interesting circuits because of the second metallic plate, turning the electrophorus into a variable capacitor:

https://www.youtube.com/watch?v=notE4ugcgvk

https://www.youtube.com/watch?v=PzoUiZnR5QA

https://www.youtube.com/watch?v=jLCp68VX7NE

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2) What about... having the same charged plate A, isolated with Teflon both sides and bringing into contact two metal plates like B each side. will "energize" them  both equaly?
yes or not?

The isolating plate (which is called "cake") has to be rubbed in order to charge it a little bit. I use real fur (fox fur) to rub the plate, which works best. Acrylic (often called Plexiglas) is a very good isolating plate and also fairly cheap. I also tried Teflon, but it was not better than Acrylic. Almost all plastic materials will work.

https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/museum/electrophorus
Citation: The basic components of an electrophorus are a flat, plate-shaped insulator, an insulating handle and a metal disk. The insulator, usually called a "cake," can be made from a variety of materials. In the days of Wilcke and Volta, researchers typically formed the cake out of shellac and resin or a kind of wax spread over glass, but any good insulator can be used. Unlike the cake, the metal disk is a conductor. In the electrophorus, the disk acts as an electrode by allowing current to pass through to a nonmetallic medium. The metal disk of an electrophorus attaches to an insulating handle and the cake stands alone.

I think that your idea number 2 will work, but that it is very impractical. One would need to arrange such an electrophorus in a vertical position.

Greetings, Conrad

[baroutologos]

Thank you conradelectro for taking your time with my thoughts and replying extensively.


I have given much thought and done some reading regarding static charges behaviour.
In generally answering to my thread.


Part 1 is doable yes and Part 2 is not. In a nutshell, the conclusion i reached is charges in stark contrast to magnetic field, (despite opposites attacts and same repel, like magnets) those of the opposite sign cancel each other whereas magnetic field always has the other pole's field extending.


cheers,
Barou


ps: excellent video!

[conradelektro]

  charges in stark contrast to magnetic field, (despite opposites attacts and same repel, like magnets) those of the opposite sign cancel each other whereas magnetic field is always has the other pole's field extending.

As far as I know, opposing electric charges do only cancel each other if they come in contact (directly or via a conductor). If they do not cancel (because they are still insulated from each other) the fields are also extending like magnetic fields. Electrically charged objects attract or repel, similar to magnets, (as long as the charge can not "flow" away) as long as they are not discharged.

Magnetism can also be transferred (like electric charge) by touching ferromagnetic, para-magnetic or dia-magnetic materials.

But magnetism and electric charge can not be compared in a trivial way, their relationship is given by the Maxwell Equations. There are no simple pictures or explanations of electricity and magnetism. One has to learn the properties and relationships, which have been described in the last 200 years.

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

https://en.wikipedia.org/wiki/Diamagnetism
https://en.wikipedia.org/wiki/Paramagnetism

Electric charge is electrons not flowing, once the electrons can flow it becomes electric current and will outomatically induce a magnetic field.

Here is a list of books which can help you:

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

https://www.amazon.de/Modern-Electrodynamics-author-Zangwill-January/dp/B00QAVX9WO/ref=sr_1_fkmr0_1?ie=UTF8&qid=1508257564&sr=8-1-fkmr0&keywords=Zangwill%2C+A.+%282013%29.+Modern+Electrodynamics+%281st+ed.%29.

I always go to the University of Vienna Library or the Technical University of Vienna Library (Austria, Vienna) to look at books. Everybody can get a library card for EUR 10.-- a year. I guess, similar options exist in other countries. Often I take pictures of interesting pages with my cell phone in order to study them at home on my PC

A lot can be learned from this web site:  hhttp://www.coe.ufrj.br/~acmq/electrostatic.html

Too many people in this forum refuse to study the absolute basics before looking for something strange. Most things discussed in this forums can easily be explained, but that would need some basic knowledge in order to be appreciated and understood.

Greetings, Conrad