Standard Capacitor Values - Electrolytic

Here is a chart in a table format showing all the standard electrolytic capacitor values available in market today.

Electrolytic Capacitor Values Chart

Currently the capacitor values shown in the table are available. Electronics suppliers tend to stock those values that are the most popular, but larger suppliers such as Farnell and RS tend to stock a wider range.

Farad

The capacitance is the capacity of a dielectric system to contain electrostatic charge, defined by the ratio Q/V where Q is the electric charge that the capacitor is capable of storing at the applied voltage V. The unit of capacitance is the "farad", and the charge is "coulomb".

Film / Foil Capacitors

These capacitors usually have a fluid within them called an electrolyte, which increases the charge storage capacity. The construction consists of two aluminium plates separated by a film, which behaves as a dielectric.

The anode has an oxide layer on its surface that acts as an electrical insulator. The second electrode is the cathode. The three layers are usually rolled into a cylindrical shape and pins welded to the foils to make the electrical connections.

Ideal Capacitor

Beginners usually think of capacitors as ideal components, however, there are many factors worth considering in precision circuits. A change in temperature will change the capacity of the dielectric system. It also exhibits a small amount of inductance and resistance. The inductance can affect high frequency operation whilst the resistance can dissipate energy in the form of heat. Capacitors wear out fast under electrical stress, and excessive heat causes their values to drift.

History

The word "capacitor" is a modern term, because in 1782 Voltaire named it condenser. The idea of the condenser dates back to the invention of the Leyden jar in 1745. It was simply a glass jar filled with water and a nail at the centre for an electrode.

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