One advantage of this type of capacitors is to have the ability to store charge Q = CV is greater when compared to other types of capacitors other, and commonly used as an element grader (filter low frequency) to the power supply circuit and can also function as coupling or decoupling the amplifier – amplifier for audio frequency (AF). High capacitance values can be obtained due to the fact that the dielectric is formed through the electrolytic process with the result that the layers are very thin, only a few nanometers. Electrolytic capacitor types can be divided into two different groups, namely of aluminum electrolytic capacitors and tantalum.
Construction-aluminum electrolytic capacitors is paper in the form of aluminum with a very high purity, reaching (99.9%) is inserted into a tub of liquid electrolyte (electrolytic process) with a certain voltage, then moved into the tub with constant speed / stable. The voltage that is connected into the electrolyte solution causes the flow of current flowing formation which amount gradually decreases when the aluminum oxide began to grow and attach to the surface of the foil.
The formation of a thin layer of aluminum oxide, which is an insulator and a dielectric capacitor. Part sheet anode (positive polarity) are coated with oxide sheet elements simultaneously rolled with a separator sheet of tissue paper on a machine spindle. Separator tissue paper is soft and thin instantly became saturated with electrolytes such as ammonium borate or ethylene glycol.
Figure 5.6. Examples of electrolytic capacitors construction
Variable Capacitors (Varco)
The variable capacitor is a type of large capacity capacitor can be changed by adjusting the vast field facing electrodes. Variable capacitors generally use an air dielectric material. Variable capacitors strung along with the inductor and resistor, is used as a tool for downloading turning radio frequency. Because it uses an air dielectric material, the capacitor has a small capacity in order picoFarrad. The following is a picture variable capacitor.
Figure 5.7. Examples of variable capacitor construction