SMD Aluminum Electrolyte Capacitor

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Aluminum electrolytics have their problems however; noise, high leakage, high temperature drift, high dielectric absorption and high inductance. Additionally, low temperature is a problem for most aluminum capacitors. For most types, capacitance falls off rapidly below room temperature while dissipation factor can be ten times higher at -25C than at 25C. Most limitations can be traced to the electrolyte. At high temperature, the water can be lost to evaporation, and the capacitor (especially the small sizes) may leak outright. At low temperatures, the conductance of the salts declines, raising the ESR, and the increase in the electrolyte?s surface tension can cause reduced contact with the dielectric. The conductance of electrolytes generally has a very high temperature coefficient, +2%/C is typical, depending on size. The electrolyte is implicated in various reliability issues as well.

Many electrolytic capacitors have a tolerance range of 20 %, meaning that the manufacturer is stating that the actual value of the capacitor lies within 20 % of its labeled value. Selection of the preferred series ensures that any capacitor can be sold as a standard value, within the tolerance. Also many electrolytic caps have asymmetric tolerances, typically -20% but with much larger positive tolerance.^[] This eliminates any need to test and grade individual caps.

A standardized set of capacitor base numbers was devised so that the value of any modern electrolytic capacitor could be derived from multiplying one of the modern conventional base numbers 1.0, 1.5, 2.2, 3.3, 4.7 or 6.8 by a power of ten. Therefore, it is common to find capacitors with values of 10, 15, 22, 33, 47, 68, 100, 220, and so on. Using this method, values ranging from 0.1 to 4700 are common in most applications. Values are generally in microfarads (?F).

Many conditions determine a capacitor's value, such as the thickness of the and the . In the manufacturing process, electrolytic capacitors are made to conform to a set of . By multiplying these base numbers by a , any practical capacitor value can be achieved, which is suitable for most applications.

The value of any capacitor is a measure of the amount of electric charge stored per unit of potential difference between the plates. The basic unit of capacitance is a ; however, this unit has been too large for general use until the invention of the , so , nanofarad and are more commonly used. These are usually abbreviated to

Case diameter:4-10mm.
Reflow soldering is available.
Ayailabe for high density surface mounting.