Simply and Accurately Measuring Dielectric Constants Using a Parallel Plate Capacitor:Sometimes You Just Can't Win

摘要

Y ou wake up one morning after covering capac-itors and dielectric constants in your physicsclass and come up with what seems to be a quick,easy, and cheap laboratory investigation: "Let'ssandwich some cheap dielectric sheets (paper)between two conducting plates (aluminum foil)to make a parallel plate capacitor. By varying thenumber of dielectric sheets (one to 12) betweenthe conducting plates and using a multimeter tomeasure the capacitance, we can find the dielec-tric constant. The plate separation is determinedby the dielectric thickness. The analysis is simple.All one has to do is graph capacitance versus thereciprocal of the dielectric thickness; the slopeshould be proportional to the dielectric constant.Perfect!" Let's go out and do it.