Ceramic Capacitors Review

Electronics, Instrumentation & Electrical Database

Ceramic Capacitors Review

Ceramic capacitors are part of the family of electrostatic capacitors. There are two types of ceramic capacitors, disc and multi-layer ceramic (MLC), and two types of MLC capacitors, surface mount type (SMT) and mono (short for monolithic). The various styles of ceramic capacitors include radial leaded ceramic disc, radial leaded monolithic, axial leaded monolithic, monolithic multi-layer ceramic, as well as packaged on tape for auto insertion (by machine to a printed circuit board). Ceramic capacitors have the following characteristics:

• Non-Polar
• Most are fixed capacitance value (the value cannot be changed by the user)
• Typically found in the lower range of capacitance values
• Available in both surface mount and radial/axial leaded styles
• Most widely used capacitor style

Another feature of ceramic capacitors is that the dielectric is comprised of ceramic materials. Simply put, the dielectric is the insulating material between the layers or plates of the ceramic capacitor. The primary reason that ceramic material is used is due to its capacity to allow electrostatic repulsion and attraction to take place across the substance. Ceramic dielectric material in a ceramic capacitor is a poor conductor of electricity while at the same time being an effective propagator of an electrostatic field. Specialty ceramic capacitor manufacturers can design component with proprietary or custom ceramic compositions, if applications require more demanding specifications than standard off-the-shelf ceramic capacitors.

Ceramic disc capacitors are used in applications where accurate, small, low-cost capacitance is required along with relatively good temperature constancy. Multi-layer ceramic capacitors (MLCs) are used where a high capacitance (up to 1 microfarad) is called for in a small space. Other features of MLC capacitors include low impedance and low voltage ratings. Multi-layer ceramic capacitors (MLCs) are useful in applications requiring the grounding of low voltage, fast rise time pulses.

Ceramic capacitors are extremely useful in decoupling and filtering applications. Other uses include switching power supplies found in computers, fax machines and modems, lighting ballasts, along with other electrical and electronic equipment. Ceramic capacitors are also found in a broad range of equipment in the defense, aerospace, medical, telecommunications and semiconductor industries.