Tantalum electrolytic capacitor

the tantalum electrolytic capacitor is an electrolytic capacitor, whose firm electrode consists of tantalum. Tantalum electrodes is wound depending upon design from foils or sintered from powder material.

Table of contents

design with foil (F)

the wound condenser uses a tantalum foil, which is rolled up together with a electrolyte-soaked paper. The tantalum foil forms the positive pole of the condenser. A thin oxide coating on the tantalum foil forms the dielectric. These condensers are specified for a temperature range from -60°C to +85°C, special types also for temperatures from -80°C to +125°C. Contrary to aluminum electrolytic capacitors they have smaller leakage currents and a smaller dissipation factor.

The higher ESR value is unfavorable compared with polymer electrolytic capacitors. Therefore with high requirements to the remaining ripple of voltage supplies polymer electrolytic capacitors are preferred as filter capacitors.

design with sinter anode and liquid electrolytes (s)

around as large a surface as possible too received, one sinters tantalum powders together to a kind metal sponge. The electrolyte, which forms the second condenser lining, penetrates into the pores. As dielectric serves also here a thin layer from Tantalpentoxid, which was produced on the surface of the tantalum interbody.

As a result of the extraordinarily large surface very large capacities per unit volume arise, how they are reached with no other condenser design.

design with sinter anode and firm electrolytes (SF)

with this condenser is pressed tantalum powders and sintered under vacuum at high temperature. The porous, open-porous tantalum body has a tantalum surface of approximately 1500 cm 2 per cm 3 volumes. The sintered compact is now formed - the tantalum surface by means of electrolysis one oxidizes. The Tantalpentoxid (TA 2 O 5) forms the dielectric. Now the formed sintered compact is dipped into a manganese connection and the cavities with it is filled. Through are converted they heat up into pyrolusite (MNO 2). This serves now as firm electrolyte and negative pole of the condenser. The manganous oxide on the surface of the body is sprayed, metallized now with graphite and soldered into a housing.

This design is particularly favourable and today in many devices is used, with which weight, size and working reliability are important - for instance in mobile telephones.

She draws out through: large capacity with smallest volume and smallest weight, long life span, good shelf-life, large frequency range and small temperature dependence of the capacity or energy dissipation.

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