Tantalum Capacitor

Tantalum Capacitors are electrolytic capacitors that is use a material called tantalum for the electrodes. Large values of capacitance similar to aluminum electrolytic capacitors can be obtained. Also, tantalum capacitors are superior to aluminum electrolytic capacitors in temperature and frequency characteristics. When tantalum powder is baked in order to solidify it, a crack forms inside. An electric charge can be stored on this crack.
These capacitors have polarity as well. Usually, the "+" symbol is used to show the positive component lead. Do not make a mistake with the polarity on these types.
Tantalum capacitors are a little bit more expensive than aluminum electrolytic capacitors. Capacitance can change with temperature as well as frequency, and these types are very stable. Therefore, tantalum capacitors are used for circuits which demand high stability in the capacitance values. Also, it is said to be common sense to use tantalum capacitors for analog signal systems, because the current-spike noise that occurs with aluminum electrolytic capacitors does not appear. Aluminum electrolytic capacitors are fine if you don't use them for circuits which need the high stability characteristics of tantalum capacitors.

The photograph on the left illustrates the tantalum capacitor.
The capacitance values are as follows, from the left:

0.33 ?F (35V)
0.47 ?F (35V)
10 ?F (35V)

Low-voltage tantalum capacitors are commonly used in large numbers for power supply on computer motherboards and in peripherals due to their small size and long-term reliability.

Due to their higher cost, tantalum capacitors were rarely used in consumer electronics, although the cheapest epoxy dipped types were sometimes used. Equipment such as medical electronics or space equipment that require high quality and reliability make use of tantalum capacitors.

The low leakage and high capacity of tantalum capacitors favors their use in circuits to achieve long hold duration, and some long duration timing circuits where precise timing is not critical. They are also often used for power supply rail decoupling in parallel with film or with low and at high frequency. Sometimes tantalum capacitors can replace aluminium electrolytic capacitors in situations where the external environment or dense component packing results in a sustained hot internal environment and where high reliability is important.

As with all electrolytic capacitors, correct polarity must be observed otherwise the capacitor will depolarize and the dielectric oxide layer will be reduced back to the metal, reducing the resistance of the device and causing it to become very hot and possibly explode. Tantalum capacitors are less prone to "drying out", causing a decrease in capacitance as is often the case with aluminium electrolytic capacitors particularly when used in hot environments. They maintain their designed capacitance under such conditions over long periods (decades).

Tantalum capacitors possess very low electrical leakage (high leakage resistance), and will retain a charge for a long duration. They are also more tolerant of hot operating environments, unlike standard aluminium electrolytic capacitors. Tantalum capacitors are relatively expensive, particularly the military grades. They are not particularly tolerant of heavy charge and discharge currents, particularly those of a repetitive nature. Their effective series resistance (ESR) is quite high when compared to aluminium electrolytics.

The cheapest form consists of a mixture of tantalum powder and manganese IV oxide pressed into a solid chalky mass around a tantalum wire, this is coated with silver and dipped into coloured resulting in a small coloured bead with two leads

A cheaper form consists of a similar tantalum billet, coated in manganese IV oxide and an electro-deposited layer of silver, this being soldered inside a tin plated brass can with an enameled glass seal at one end.

In tantalum capacitors, the anode consists of a small cylindrical billet of tantalum metal held inside a can, which forms the cathode, by spacers. A tantalum lead exits the can via a teflon and at one end. This tantalum lead is to a copper lead outside the can. An electrically conductive jelly fills the space between the inside wall of the silver can and the surface of the tantalum billet, which is covered by the steel blue layer of oxide which is the dielectric barrier.

The tantalum capacitor is a highly reliable type of in which the is formed from a very thin layer of pentoxide.

Performance is stable, does not change with changes in the environment, can be characterized by large capacity value.
Tantalum