0 Members and 1 Guest are viewing this topic.

Capacitance is the capability of a material object or device to store electric charge. It is measured by the charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: self capacitance and mutual capacitance.[1]: 237?238 An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operation of the capacitor, an elementary linear electronic component designed to add capacitance to an electric circuit.The capacitance between two conductors is a function only of the geometry; the opposing surface area of the conductors and the distance between them, and the permittivity of any dielectric material between them. For many dielectric materials, the permittivity, and thus the capacitance, is independent of the potential difference between the conductors and the total charge on them.The SI unit of capacitance is the farad (symbol: F), named after the English physicist Michael Faraday. A 1 farad capacitor, when charged with 1 coulomb of electrical charge, has a potential difference of 1 volt between its plates.[2] The reciprocal of capacitance is called elastance.

As I always say, AC hurts more than DC and the reason is human body capacitance. Let's see how big this capacitance is.

There is only one, where c=q/v.

Capacitance is simply the ability to hold charge, same as the volumetric capacity of an inflatable fluid container. Various methods of achieving this "capacitance" is what that wiki article is describing, NOT different types, as there is only one. Similarly one may find mention of self inductance and mutual inductance but there is only one inductance.

This tutorial video shows how to estimate / measure the self-resonant frequency (SRF) of a capacitor using an oscilloscope and a signal generator.The video also mentions some caveats to be aware of when attempting this. In addition to those mentioned in the video, there are more... The parasitic inductance of the fixture and probe should be substantially lower than the parasitics of the capacitor under test. For small RF capacitors, well under 1nF for example, this is especially important. Special RF fixtures would be needed to accurately measure the SRF. There are several other factors that can influence this measurement, but the basic concept works well for capacitors used for DC bypassing, broadband signal coupling, etc. For RF applications, it is much more difficult to apply this method and get accurate results.