Mica is a natural material and not available in unlimited quantities. Prior to World War II, mica was the most common dielectric for capacitors in the United States. Mica dielectric capacitors were invented in 1909 by William Dubilier. On the receiver side, the smaller mica capacitors were used for resonant circuits. These materials some decades later were also well-suited for further use as the dielectric for the first capacitors.Įven in the early years of Marconi's wireless transmitting apparatus, porcelain capacitors were used for high voltage and high frequency application in the transmitters. Since the beginning of the study of electricity non-conductive materials such as glass, porcelain, paper and mica have been used as insulators. 5.3 Features and disadvantages of ceramic capacitors.4.11 Insulation resistance and self-discharge constant.4.9 HF use, inductance (ESL) and self-resonant frequency.4.8 ESR, dissipation factor, and quality factor.4.4 Frequency dependence of capacitance.4.3 Temperature dependence of capacitance.4.2 Capacitance standard values and tolerances.3.1.9 RFI/EMI suppression with X- and Y capacitors.3.1 Multi-layer ceramic capacitors (MLCC).Ĭeramic capacitors of special shapes and styles are used as capacitors for RFI/EMI suppression, as feed-through capacitors and in larger dimensions as power capacitors for transmitters. Class 2 ceramic capacitors offer high volumetric efficiency for buffer, by-pass, and coupling applications.Ĭeramic capacitors, especially multilayer ceramic capacitors (MLCCs), are the most produced and used capacitors in electronic equipment that incorporate approximately one trillion (10 12) pieces per year.Class 1 ceramic capacitors offer high stability and low losses for resonant circuit applications.Ceramic capacitors are divided into two application classes: The composition of the ceramic material defines the electrical behavior and therefore applications. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes. Fixed leaded disc and multilayer ceramic chip capacitors (MLCC)Ī ceramic capacitor is a fixed-value capacitor where the ceramic material acts as the dielectric.
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