[Capacitor](By Eric Schrader from San Francisco, CA, United States - 12739s, CC BY-SA 2.0, Link)
There is an opinion or even the assertion that a direct current does not pass through the capacitor, but the alternating current passes. This is fundamentally not true.
First, the division into alternating and direct current is conditional. Alternating current is a repetitive and directional direct current that changes direction.
A capacitor is an appliance that is capable of storing electricity, storing it and giving it away when it is closed. Nothing reminds you, of course this is such a kind of battery. The battery should work and it's charged - discharged, charged - discharged.
[Types of Capacitor.](By Uploader is Jwratner1 at English Wikipedia. - Vectorized from raster image at English Wikipedia., CC0, Link)
Let's include the capacitor in the DC circuit, and see what happens. A current will flow through it, so the circuit will close and it will be charged. The time interval for which the capacitor is charged is very small, this is its main difference from the battery, but the discharge time in the aftermath is just as small ...
[Direct Current (red line). The vertical axis shows current or voltage and the horizontal 't' axis measures time and shows the zero value.](By Zureks - Own work, Public Domain, Link)
The direct current through the capacitor passes, but only not very long, exactly as long as it is charging. After that, it needs to be discharged, but nowhere, since it is constantly under charging voltage. When plugged into an alternating current circuit, when the current changes direction to the counter-current, the capacitor discharges, which makes it again ready for a new charge when changing the direction of the current. And this happens all the time, which creates an appearance in the observer about the flow of alternating current through the capacitor.
In addition to the capacitor, there is such a device as an supercapacitor . This is something like a mixture of a capacitor and a battery. Such devices have a large capacity. It has a low charge-discharge voltage but high currents, which makes them available for use in power electronics. For example, a very topical problem of charging eoctro cars, which can be solved with the help of supercapacitor .
[Typical construction of a supercapacitor: (1) power source, (2) collector, (3) polarized electrode, (4) Helmholtz double layer, (5) electrolyte having positive and negative ions, (6) separator.](By Tosaka - Own work, CC BY 3.0, Link)
In procuring. All devices or materials conduct electricity, but to some extent. The materials that we call insulators have a high resistance to electricity and can be used in capacitors as a diode. So that's how we found out once the eco-tricity they are trying. But the quantity of this electricity is so small that we are not able to determine it. But we still operate with other quantities, more plural, strong and large, if I may say so. We can not define single properties. Milliken needed to put a very complex experience in order to determine the minimum charge. And how to determine the minimum current discreteness. We operate with constantly recurring currents for periods of time far exceeding the times of existence of phenomena at the speed of light. This is not our league. We are still in the Stone Age.
[Battery of four Leyden jars in Museum Boerhaave, Leiden, the Netherlands](By Alvinrune at the English language Wikipedia, CC BY-SA 3.0, Link)
