A capacitor possesses the capacity to store electrical power. The word capacitor comes from the word capacity. Circuits rely on capacitors to store electrical power. The role of power factors as power storage devices in power circuits can hardly be overstated. Capacitors are the only means of storing electrical power after batteries. In addition to storing energy, capacitors can also improve power quality.
The role of capacitors in electronic circuitry, however, varies greatly. Ceramic is a material that has been very useful in the development of miniaturized capacitors for electronic circuits and this is why ceramic capacitors have been developed. Although capacitors come in diverse types and capacities, high voltage ceramic capacitors are the most commonly used capacitors. In the following discussion, we will focus on ceramic capacitors only.
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Ceramic Capacitors Are Capacitors That Are Made Of Ceramic.
It consists of a ceramic dielectric layer between layers of conducting foils/plates with a fixed capacitance value in micro or pico farads. Ceramic is being used as a suitable medium because it is nonconductive and non-metallic, and able to retain electric charge even at high temperatures.
Symbol and Polarity of Ceramic Capacitors
Due to the non-polar nature of the ceramic capacitor, it can be used with any polarity and supply (AC/DC). Here is a universally accepted symbol for a ceramic capacitor.
Construction of Ceramic Capacitors
In capacitors, ceramics were used because of their superior dielectric and insulating properties. The properties of ceramics made them ideal for capacitor construction.
Different sizes and shapes of capacitors are available. Electrodes (plates) have a high capacitance whose value greatly varies with their surface areas. Hence, we use a multi-layer construction to increase surface area, resulting in a compact and small device with higher capacitance. A parallel connection would give the same effect. Multi-layer ceramic capacitors (MLCC) are also known as these types of capacitors.
Above, a multilayer ceramic capacitor is shown where electrolytes are terminated and ceramics between electrodes are placed. Capacitors made of ceramic can also be chip or dish shaped and have small capacitance values of the order of pico or nano Farads (unit for measuring capacitance). Ceramic is used as the filler between the two electrodes in a dish type construction, which is composed of two small circular dishes.
Ceramic Capacitor Characteristics
There is a great deal of overlap between the characteristics of ceramic capacitors and those of ceramic dielectrics and their construction (monolithic or multilayer). To make ceramic capacitors have the desired characteristics, titanium dioxide is mixed with additives.
These capacitors offer the following characteristics: They can be miniaturized, they can handle high voltages, and they have an accurate capacitance value. Capacitors made of multilayer ceramics have a broad spectrum of frequency applications.
Our capacitors can be made with the least amount of variation in capacitance over a broad range of temperature changes by modifying the dielectric composition. Temperature compensated capacitors are made in this way. It is also possible to design ceramic capacitors to perform under wide frequency variations and with high dielectric constants.