Allied Encyclopedia – Capacitance in Coaxial Cables

Allied EncyclopediaCapacitance is a difficult thing to wrap your head around. Most sources try to explain it using scientific terms, and that just makes it more complicated and confusing! Here’s a look at capacitance in terms we can all understand.

First, let’s define “capacitor” to give us a better idea of what we’re working with. A capacitor is a passive electronic component, meaning that it does not produce energy, but has the ability to store it.

Capacitors are made up of two plates that electricity can flow through, known as conductors, separated by a dielectric or insulating material in the middle.

When the two conductors in the capacitor have different potentials, which is to say that they have different values for the energy each can give off, each plate’s electric charges are pushed away from them and into the insulating material between.

This insulating material has the ability to store electric charge. The amount of energy stored here and the ability of the capacitor to hold that charge are known as its capacitance. As a rule, a larger capacitance means that it can hold more charge.

With capacitance, many times, lower is better. For example, in instrument cables, a lower cable capacitance allows more of the natural sounds of the instrument to reach the amplifier. With higher capacitance, some of the high frequency sounds are trapped in the insulation and unable to come through. Similarly, with data cables, high capacitance can slow down voltage movement and distort the signal or “pulse” that finally reaches the circuitry. In this case, lower capacitance also allows the cable to perform better at high frequencies.

In general, the amount of capacitance usually depends on the surface area of the conductors/plates as well as the distance between them. The unit of measurement for capacitance is the farad, but for cables, the amount is usually measured in smaller picofarads.

Although capacitance is still a very complex topic, we hope we were able to give you a better understanding of the term, as well as some useful information on how it works and how it is measured.

About awcwire
Allied Wire & Cable is a value-added manufacturer and distributor of electrical wire and cable, tubing, and more. We are a family owned and operated company, serving a wide range of industries, including the military, automotive, aerospace, and telecommunications markets. Allied is headquartered in Collegeville, PA. Additional locations can be found across the US, in Phoenix, AZ; Bedford, NH; Pewaukee, WI; Rochester, NY, Tampa, FL; and Mt. Juliet, TN. For more information on Allied, visit our main website at

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