Embedded Lab

Dielectrics are insulators that are used to separate the charged plates in capacitors. The insertion of the dielectric material enhances the charge storing capacity, and hence the capacitance, of the charged plates. Dielectric materials are characterized by what is called dielectric constant, and is defined as the ratio of the capacitance using the material in between the plates, compared to a similar capacitor that has vacuum as its dielectric. Steven Dufresne from Hackaday covers in this tutorial article the basics of dielectric materials and a practical method to measure the dielectric constant using a multimeter.

Measuring dielectric constant of a dielectric material

Every now and then you need to make your own capacitor. That includes choosing a dielectric for it, the insulating material that goes between the plates. One dielectric material that I use a lot is paraffin wax which can be found in art stores and is normally used for making candles. Another is resin, the easiest to find being automotive resin used for automotive body repairs.

The problem is that you sometimes need to do the calculations for the capacitor dimensions ahead of time, rather than just throwing something together. And that means you need to know the dielectric constant of the dielectric material. That’s something that the manufacturer of the paraffin wax that makes it for art stores won’t know, nor will the manufacturers of automotive body repair resin. The intended customers just don’t care.