Ceramic Capacitor Introduction
Ceramic Capacitor Introduction
A ceramic capacitor is a fixed value capacitor in which ceramic material acts as the dielectric. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes. The composition of the ceramic materialdefines the electrical behavior and therefore applications. Ceramic capacitors are divided into two application classes:
Class 1 ceramic capacitors offer high stability and low losses for resonant circuit applications.
Class 2 ceramic capacitors offer high volumetric efficiency for buffer, by-pass and coupling applications.
Ceramic capacitors, especially the multilayer style (MLCC), are the most produced and used capacitors in electronicequipment that incorporate approximately one trillion pieces (1000 billion pieces) per year.
Ceramic capacitors of special shapes and styles are used as capacitors for RFI/EMI suppression (Typically STE's Y Capacitors), as feed-through capacitors and in larger dimensions as power capacitors for transmitters.
The different ceramic materials used for ceramic capacitors, Para electric or ferroelectric ceramics, influences the electricalcharacteristics of the capacitors. Using mixtures of Para electric substances based on titanium dioxide results in very stable and linear behavior of the capacitance value within a specified temperature range and low losses at high frequencies. But these mixtures have a relatively low permittivity so that the capacitance values of these capacitors are relatively small.
Higher capacitance values for ceramic capacitors can be attained by using mixtures of ferroelectric materials like barium titan ate together with specific oxides. These dielectric materials have much higher permittivity's, but at the same time their capacitance value are more or less nonlinear over the temperature range, and losses at high frequencies are much higher. These different electrical characteristics of ceramic capacitors require grouping them into “application classes”. The definition of the application classes comes from the standardization. As of 2013, two sets of standards were in use, one from International Electro technical Commission (IEC) and the other from the now-defunct Electronic Industries Alliance.