A capacitor is a type of electrical reservoir that stores and releases electric energy. This type of item is used in the production of many devices, such as amplifiers, computers, televisions, radios etc. You can find some of the components mentioned above in almost all electronic circuits.
Since they basically host an electric charge, their voltage and capacities can apply to a large variety of needs. Producers use a lot of materials to create capacitors according to the area of usage.
Ceramic
Usually, capacitors are designed as sandwiches of insulators placed between 2 layers of metal. An insulator is made out of a material called “dielectric” and it determines the general behavior of the capacitor. The devices that have a ceramic dielectric have smaller values (they start at a couple of picofarads- the farad is the unit of capacitance) and can reach even a thousand picofarads. An interesting thing about them is that they have great capacitance stability when it comes to a large temperature range.
Tantalum
The items that need to fit a large capacitance value in a tiny space can easily use tantalum capacitors. They are polarized (one lead takes positive charges while the other one negative ones). Extra attention should be given in order not to Tantalum Wire the capacitor backwards or the polarity might destroy it. You can recognize a bad capacitor by the silvery fluid released.
Aluminum Electrolytic
This is used for the stronger applications and the power-supply filters. It is not very expensive and has a tolerance of 20%. This means that they normal value of the part can vary higher or lower than the value displayed on the label.
One of the most significant issues in this case is represented by the liquid inside, which can dry and prevent the capacitor from working. The liquid can also leak and destroy the rest of the components. Furthermore, the electrolytic capacitors can explode if they are connected in a wrong manner, they can leak current, do not have a long lifespan and do not resist to high temperatures.
Polyester Film
This type of capacitors has a greater capacitance value and it is very reliable. Its capacitance increases when the temperature does, making it incompatible with sensitive circuits. These capacitors can be found in various locations and do not cost very much.
Silver Mica
This is also a great dielectric. Mica is a natural mineral which creates thin sheets. It has a very accurate part values, it is very reliable, but its price is a bit higher compared to other capacitors. It is used especially for the frequency-sensitive parts of the radio and audio circuits. In this case, the capacitance value starts at a couple of picofarads and goes up to very low microfarads.