Electrolytic capacitors:
These types of capacitors are usually in the micro-farad range. Electrolytic capacitors are the same as fixed capacitors, but their size and capacity are larger than fixed capacitors. Another name for these capacitors is chemical. The reason they are called so is that the dielectric impregnates these capacitors with a type of chemical that, in practice, acts as a catalyst, increasing the capacitance of the capacitor.
Unlike lens capacitors, these capacitors have positive and negative poles or bases. On the body of the capacitor next to the negative base, the sign – is written. The actual value of their capacitance and tolerable voltage is also written on the body. Electrolytic capacitors are made in two types of aluminum and tantalum.
1.Aluminum capacitor
This capacitor, like sheet capacitors, is made up of two aluminum sheets. One of these sheets on which the oxide layer is formed is called the “anode” and the other aluminum sheet acts as a cathode.
Its internal structure is such that two sheets of aluminum with two layers of porous paper between them are wrapped at the same time and the connecting wires are connected to the ends of the aluminum sheets.After wrapping the sheets, it is immersed in a suitable electrolyte that accelerates the formation of the oxide layer to fill two layers of porous paper with electrolyte. The whole set is then placed inside a metal frame and tightly closed with a plastic pole through which the capacitor wires pass.
2.Tantalum capacitor:
In this type of capacitor, tantalum metal is used instead of aluminum. The high dielectric constant of tantalum oxide compared to aluminum oxide (about 3 times) causes tantalum capacitors to have more capacity than the aluminum type in equal volume.
The advantages of tantalum capacitor compared to aluminum type are as follows:
Smaller leakage current dimensions, shorter service life. Among the disadvantages of this type of capacitor compared to aluminum capacitors are:
Tantalum capacitors are more expensive. They are also more sensitive to increasing the applied voltage against its allowable voltage, as well as reversing the polarity. They can not withstand high charge and discharge currents. Tantalum capacitors have a capacity limit (up to a maximum of 330 micro-farads).
Models of electrolytic capacitors:
SCREW TERMINALS
SNAP-IN
SOLDER TERMINALS
MOTOR START-CAPACITORS
S-TYPE CAPACITORS
AXIAL-LEAD
AXIAL LONG LIFE CAPACITORS
LONG LIFE CAPACITORS
PHOTO FLASH-CAPACITORS
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