What are Wet Tantalum Capacitors?

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Editorial Team - everything PE

Sep 7, 2022

Wet tantalum capacitors consist of electrolytic capacitors with an anode, a cathode, and a wet electrolyte. They offer high volumetric efficiency, high reliability, electrical stability over a wide temperature range, and a long lifetime. Wet tantalum capacitors are ideal for military, aerospace, satellite industry, and heavy industry applications.

Wet tantalum capacitors have a self-healing mechanism. The oxide layer, which serves as the capacitor's dielectric when it is compromised, is restored through a chemical process in self-healing. Capacitor corruption results from oxide layer degradation. Of all electrolytic capacitors, tantalum wet capacitors have the lowest leakage current. In the presence of voltage, the capacitor draws a parasitic current called leakage current. For instance, a capacitor with a low leakage current is a good choice for the sample and hold circuits because it won't discharge itself over time due to leakage current and will hold the charged voltage for a long time.

New designs of wet tantalum capacitors use a sintered tantalum pellet cell and a gelled sulfuric acid electrolyte mounted in a pure tantalum case to address issues with silver migration and whiskers that previously increased leakage currents and short circuits.

Wet tantalum capacitors could use sulfuric acid as an electrolyte and have a relatively low ESR because the tantalum dielectric oxide layer is inert and stable in strong acids.