In electronic circuit, one of the common component will found is capacitor.
There are several types of capacitors can be found on the market today. Each type of capacitor is design for specific application.
Capacitor are important in application dc blocking, coupling, filtering, smoothing, timing, storing energy and oscillator.
Polarized and Non-Polarized Capacitor
Polarized Capacitor
Polarized capacitor means the capacitor have polarity positive and negative. It used in DC application. Normally, the polarized capacitors offer higher capacitance value, but they have higher leakage current and act as a short circuit when connected in wrong polarity. It have lower frequency response, is up to around few MHz.
Non-Polarized Capacitor
Non-polarized capacitor means the capacitor have no polarity positive and negative. It used in AC and some DC application also. The non-polarized capacitor offer lower capacitance value, but they have lower leakage current value. It have wider frequency response, it frequency response can up to GHz.
2 identical polarized capacitors back to back with one of them reversed will become non-polarized capacitor with half the capacitance. It not recommend used in circuit, because you need to find the match pair capacitor. The unbalance of capacitor's leakage current, can reduce the capacitor life span.
Capacitor Type
Electrolytic Capacitor - The Electrolytic capacitors (Aluminum Electrolytic Capacitors) are polarized capacitor. They are offer high capacitance value - typically 1uf and above. Normally, it use in low frequency applications - power supplies, coupling or decoupling audio, and filtering. Three easy ways to destroy an electrolytic capacitor :-
a) Over-Voltage - over voltage will cause current to leak through the dielectric resulting in a short circuit condition. Beside that, the over voltage can cause an capacitor temperature increase.
b) Reversed Polarity - reverse voltage will cause self-destruction of the oxide layer.
c) Over Temperature - over heat dries out the electrolytic and shortens the life of an electrolytic capacitor.
Tantalum Capacitor - Tantalum Capacitor is better quality polarised capacitor. They are offer very high capacitance value and smaller size. Its failure mode tends to be a short-circuit, therefore, the failure tantalum capacitor often have burn mark or exploding. They must also not be subject to high ripple currents or voltages above their working voltage, or reverse bias.
Ceramic Capacitor - The ceramic capacitor is a type of capacitor that used in AC applications from audio to RF. Its value range is start from few picofarads up to around 0.1 microfarads.
