Ch 25: Capacitors & DielectricsWorksheetSee all chapters
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Concept #1: How Dielectrics Work

Transcript

Hey guy. In this video we're going to be talking about how dielectrics work, okay? The little nitty-gritty stuff, alright? Let's get to it. What a dielectric is specifically is it's an insulating material that has the ability to polarize, we talked about polarization a while ago when we were discussing how objects gain charge, okay? On the left here, I have an insulator that's left alone, it has no external electric field. So, all of those atoms, right? Which are a positive and negative charge are oriented in all sorts of random directions, okay? This is non polarized, however, when I put this insulating material in an external electric field then the charges want to align themselves in a particular way, okay? These negative charges want to move up to the, sorry, down the electric, yeah, up the electric field, right the first time, and these positive charges want to move down the electric field. So, they all orient themselves in a specific way to align with the electric field, this is a polarized insulator. So, an insulator that has the ability to polarize is a dielectric. Now, how did dielectrics affect capacitors? This is another thing that we want to look at at the atomic level, consider the capacitors shown that has a small dielectric placed partially inside of it, what happens is, in the vacuum this capacitor produces five electric field lines, the thing is that the dielectric has charges, for instance, negative charges that can absorb some of those field lines so they don't pass through the dielectric and then positive charges that then produce those same field lines again, okay? So, inside the dielectric the actual amount of electric field lines is reduced, dielectrics reduce the electric field, we can see from this figure that there are only two electric field lines inside the dielectric. So, in a vacuum the electric field is going to be one value but inside the dielectric is always going to be less, okay? This wraps up our discussion about how dielectrics work on the atomic level, okay? All this nitty-gritty stuff about dielectrics, thanks for watching guys.