I thought I knew where the charge in the capacitor was. Physicists' experience shows the opposite
From the school physics course, we know that the charge in a capacitor is on its conductive plates:
According to the formulas, the charge of a capacitor (in Farads) depends on the area of the plates, the dielectric constant of the dielectric and the charge transferred to it in Coulomb. It all works, the formulas are correct. And no one questioned the assertion that the entire charge of a capacitor is contained precisely on its plates. Even the breakdown of the capacitor says: why check it?
A few years ago, I came across a video where one researcher at home set up an experiment: loading a simple homemade capacitor (two metal plates and a sheet of plastic), removed the plates, connected them together and no discharge observed. Then he laid the dielectric in another place between the plates - the discharge of the capacitor also not observed.
Then he took another pair of plates that did not participate in the experiment, laid the dielectric with the initial charging point between them and closed -
the capacitor was discharged. Those. the charge in the capacitor, judging from his experience, is exactly not on the covers. Charge is in dielectric (or on its surface) and strictly in a certain place.- How can this be? See for yourself - link for this video 2013.
The same experience was repeated by teachers from Novosibirsk State University:
The authors did even more experiments with plates and dielectric and showed convincingly that the charge is concentrated in the dielectric. Moreover, this charge can be removed only by creating a new capacitor with its participation (even if the leading hands are the plates). They succeeded charge the plastic without participating in the experiment of one capacitor plate. And when the capacitor was assembled, the discharge proved this fact.
In experience not confirmed and the assumption that the charges are concentrated on the dielectric surface (experiment with two dielectric plates). This is how the myths about the charges on the capacitor plates are debunked. I'm probably not the only one.
I decided to look for answers and an explanation of this experience and phenomenon. It turned out that this has long been known and is described by the Gauss theorem for electrostatics.
More details can be found in the tutorial: Sivukhin D.V. General course of physics, volume 3, page 63. Link: http://4ipho.ru/data/documents/Sivuhin_III.pdf
But this information is for those who are especially savvy in physics. For us, ordinary people, everything can be explained as follows:
The phenomenon can be explained by materials called electrets. This is a type of dielectric that has the property of a long time maintain a polarized state. Those. they have within their structure dipoles and the dipoles can orient themselves when an electric field is applied to them. there is hetero and homocharged electrets. The former are polarized in volume, while the latter are transferred by electrons from the plates of the electrically conductive material.
So in the experiments of researchers - just dielectrics that are close to electrets or are them.
But I'm wondering if this effect will manifest itself with a variable-capacity air condenser if you blow it with air from the compressor. Will it lose charge or will the charge remain?
The idea is that electrified air will move with a stream of air and carry away the charge. This is also confirmed by the rapid self-discharge of the air condenser. Write your thoughts in the comments.
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