Tantalum electrolytic capacitor is a kind of electrolytic capacitor. Widely used in communications, aerospace and military industry, submarine electricity and high-end electronic equipment, civil electrical appliances, television and other aspects.
Tantalum electrolytic capacitors are made of metal tantalum (Ta) as anode material. According to the rejection of anode structure, they can be divided into foil type and tantalum sintered type. In addition, due to the rejection of working electrolyte, tantalum sintered type tantalum capacitors can be divided into solid electrolyte tantalum capacitors and non-solid electrolyte tantalum capacitors. Meanwhile, the amount of solid tantalum electrolytic capacitors is large, such as CA type, CA42 type, etc.
The shell of tantalum electrolytic capacitors has the CA symbol, but in the circuit symbol and other electrolytic capacitor symbol is the norm. The most common tantalum capacitor structure is shown in the figure above.
Compared with aluminum electrolytic capacitors, tantalum electrolytic capacitors have the following advantages.
1. Small size Because tantalum capacitors use very fine tantalum powder, and the dielectric constant of tantalum oxide film is 17 higher than that of aluminum oxide film, so the capacitance per unit volume of tantalum capacitor is large.
2.Generally, tantalum electrolytic capacitors can operate normally at the temperature of -50℃~100℃. Although aluminum electrolysis can also operate within this plan, its electrical function is far worse than tantalum electrolysis.
3. Long life, high insulation resistance, small leakage current tantalum electrolytic capacitor tantalum oxide film medium is not only corrosion resistant, and long-term operation can adhere to the excellent function.
4. The impedance frequency characteristic is good for the frequency characteristic of the capacitor, when the operation frequency is high, the capacitance will decrease greatly, and the loss (TG δ) also rises sharply. But solid electrolytic capacitors can operate above 50kHz. As the frequency rises, the tantalum capacitor's capacity also decreases, but the fluctuation is small. According to materials, when the operation is at 10kHz, the tantalum capacitor's capacity decreases by less than 20%, while the aluminum electrolytic capacitor's capacity decreases by 40%.
5. Firmness The chemical function of high tantalum oxide film is stable, and because the tantalum anode matrix Ta2O5 is strong in acid and alkali, it can use solid or liquid electrolyte with low resistivity containing acid, which makes the loss of tantalum electrolysis smaller than aluminum electrolysis capacitor, and the temperature stability is excellent.