Tantalum capacitors are electrolytic capacitors which use tantalum metal as the anode and passivated tantalum pentoxide as the dielectric. They are polarized capacitors with superior frequency and stability characteristics. Their capacitance doesn’t change with age significantly.
Please note that tantalum capacitors are very sensitive to reverse polarization. If a reverse polarity voltage is applied, the dielectric oxide breaks down, sometimes forming a short circuit. This short circuit may later cause thermal runaway and destruction of the capacitor.
Comparision between different kinds of capacitors
| Type | Aluminum Electrolytic | Multilayer Ceramic | Tantalum | Film |
|---|---|---|---|---|
| Dielectric | Aluminum Oxide | Several Ceramics | Tantalum Pentoxide | Plastic Film |
| Advantage | Wide array of breakdown voltages and capacitances |
Good high frequency characteristics. No polarity |
Small package. Large, stable capacitance |
High breakdown level No polarity. |
| Disadvantage | Electrolyte leakage limits life. Large package size. Polarity |
Capacitance varies depending on voltage and temperature. Cracking/Chipping possible. |
Short-Circuit possible. There is polarity |
Small Capacitance Less package variety. |