Ceramic Capacitor: Types, Properties and Applications

A ceramic capacitor is a fixed-value capacitor having ceramic material as a dielectric. It can have a capacitance in the range between 1nF to 1µF, however, values as high as 100F are also possible. 

• It's constructed using multiple alternating ceramic layers along with a metal layer. 
• The most commonly used ceramic capacitors of modern electronics are the multi-layer ceramic capacitor (MLCC) and the ceramic disc capacitor. 
• The wide application of ceramic capacitors in various fields is parallel to their durability, reliability and affordability. 

Key Terms: Ceramic Capacitor, Ceramic Material, Capacitance, Dielectric, Disc Capacitors, Multi-layered Disc Capacitors (MLCCs),

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What is a Ceramic Capacitor?

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A Ceramic Capacitor is a type of Capacitor that utilizes ceramic or Porcelain discs as the dielectric material. Ceramic material is a well-known insulator and can efficiently function as a dielectric while the metal layer acts as Electrodes.

• The composition of the ceramic material used in a ceramic capacitor decides the electrical behaviour along with its applications. 
• The set-up of a Ceramic Capacitor is shown in the diagram below:- 

Ceramic Capacitor

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What kind of material is Ceramic?

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Cеramic is a typе of inorganic, non-mеtallic matеrial that is typically composеd of a combination of mеtallic and non-metallic еlеmеnts, primarily oxygеn, along with othеr еlеmеnts likе silicon, aluminum, and various mеtal oxidеs.

• Cеramics arе known for their high mеlting points, hardnеss, and ability to withstand high tеmpеraturеs and harsh еnvironmеntal conditions. 
• The main elements in ceramic are carbon, nitrogen, silicon, oxygen as carbide, nitride, silicates and oxides respectively.

Read More: Combination of Capacitors

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What's the term Ceramic Capacitor Polarity?

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While using Capacitors in any circuit one must keep in mind the nature of the Polarity of the Capacitor to avoid any damage. Usually, a capacitor can be either-

• Polarised
• Non- Polarised

Polarised

A polarised capacitor has both terminals with opposite charges, making the capacitor polarized. One terminal will be the Anode and the other one will be Cathode. The user has to make proper connections for the Cathode and Anode terminals.

Non-Polarised

On the other hand, a Non- Non-polarised capacitor is one with no polarization at its terminals and hence, it is non-polarised. 

• Such a capacitor can be connected in any configuration in a circuit.
• Its terminals have no polarities and can be connected in any way in a circuit. 
• This property makes it suitable for use in AC circuits. 

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Types of Ceramic Capacitors

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The two most commonly used ceramic capacitors are:-

Ceramic Disc Capacitors 

Ceramic disc capacitors are the ones having ceramic discs coated with silver contacts on both sides. Multiple layers can be done to give larger capacitances. 

• Ceramic Disc Capacitors are often used as safety capacitors in electromagnetic interference suppression applications.
• Ceramic disc capacitors are usually bulky and have become obsolete. 
• In many electronic equipment MLCCs are being used nowadays. 
• Ceramic disc capacitors can have a capacitance value falling anywhere between 10pF to 100μF. 
• It also has a wide variety of voltage ratings, between 16 V to 15 kV and more. 

Multi-layered Ceramic Capacitors (MLCCs)

Ceramic capacitors with multilayer style (MLCC) are widely prevalent in electronic equipment. Multi-layered Ceramic Capacitors (MLCCs) are manufactured by mixing finely ground granules of paraelectric and ferroelectric materials in accurate proportions and then layering the mixture with metal contacts in an alternate fashion.

• The resultant mass is then sintered at high temperatures to achieve the desired properties in the Ceramic material. 
• The layers in an MLCC can be as many as 500 or more with a minimum thickness of 0.5 microns between two adjacent layers. 
• A large number of layers increase the capacitance in the same proportion. 
• These types of capacitors technically, consist of many smaller capacitors connected in parallel (product of alternate layering)
• Thus, increasing the overall capacitance of the device.

The uses are mentioned:

• MLCCs are mostly used in feed-through capacitors along with larger dimensional systems as power capacitors in transmitters. 
• It is also used in RFI/EMI suppression systems.

The dielectric materials used in Ceramic capacitors vary from one manufacturer to another, but common compounds include titanium dioxide, Strontium Titanate, and Barium Titanate.

Read More: Energy Stored in a Capacitor

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Features of Ceramic Capacitors

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The features of Ceramic Capacitors are mentioned below:

Tolerance and Precision

The Class 1 Ceramic Capacitors are very accurate and the capacitance value is stable for a wide variety of applied voltage, frequency and temperature. 

• These are used where high stability and low losses are required. 
• Class 2 capacitors offer high capacitances per volume and hence, it can be utilized for less sensitive applications. 
• Thus, Ceramic Capacitors offer accuracy, stability and high capacitances with little loss of energy.

High Voltage and Power

Ceramic Capacitors, particularly, Power ceramic capacitors having larger built have the ability to withstand high voltages. 

• These possess specialised terminals for safe connection to a high-voltage supply.
• The voltage Tolerance limit of such Ceramic Capacitors can be between 2kV up to 100 kV, with a power specified at much higher than 200 volt-amperes.
• Small-sized MLCCs used in printed circuit boards can hold voltages from only a few volts up to several hundreds of volts, depending on the application.

Advantages due to Small Size

There is a need for high component packing densities, especially in most modern printed circuit boards (PCBs). 

• Ceramic Capacitors are of immense potential in such cases as compared to other capacitors.
•  For instance, a “0402 multi-layer ceramic capacitor package measures just 0.4 mm x 0.2 mm. 

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Different Classes of Ceramic Capacitors

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Ceramic Capacitors can be classified into the following four classes, depending on working temperature range, tolerance, temperature drift and usage:-

Class 1 Ceramic Capacitor 

It works efficiently when it comes to stability and loss. Used in oscillators and filters as these have relatively lower losses of energy. These have stable temperature coefficients making them suitable for high Tolerance capacitors. Magnesium Titanate is used for a positive temperature coefficient and Calcium Titanate for a negative temperature coefficient.

• These have almost linear characteristics. 
• The performance of the ceramic capacitor dielectric is defined by three types of characters, the first character being significant figure changes in capacitance with respect to temperature.
• The second character is numeric which gives the multiplier.
• The third character is a letter that gives the maximum error in the values of ppm/C.

Class 2 Ceramic Capacitor

Its capacitance is influenced by the Applied Voltage. Class 2 dielectric Ceramic Capacitors have a non-linear temperature coefficient. These are used in electronics where coupling, decoupling and bypass applications are required.

• The performance of Class 2 Ceramic Dielectric Capacitors is also based on three characteristics. The first character is the letter explaining the low-end operating temperature.
• The second character is a numerical denoting the high-end operating temperature.
• The capacitance change with respect to temperature is shown by the third character. 

Class 3 Ceramic Capacitor 

The values of permittivity for class 3 Ceramic Capacitor dielectrics are exceedingly high, up to 50,000 times when compared to class 2 dielectrics. These provide high volumetric efficiency.

• The disadvantage of Class 3 Ceramic Capacitors is that these offer poor accuracy (commonly, 20%, or -20/+80%) and a low dissipation factor. 
• The dielectric used for such capacitors is often Barium Titanate.
• It is used in decoupling or in other power supply applications where accuracy is not needed.

Class 4 Ceramic Capacitor 

The Class 4 type is also referred to as Barrier Layer Capacitor. These make use of Ceramic materials with high dielectric constants and have a Surface barrier layer or surface barrier Boundary layer.

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Applications and Uses of Ceramic Capacitors

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Due to its compact size, ability to withstand high voltage, large capacitances and immense stability, ceramic capacitors are used in millions of Electronic Devices and Gadgets available in the Market. Some of these are:-

• Power Supply Circuits (for Coupling needs)
• In communication systems like RF and Microwave Circuits 
• Electronic devices like Watch, Clocks and Microcontroller (as a part of the oscillators and resonators 
• In Printed Circuit Boards (PCBs)
• Audio / Radio frequency signals (for Coupling signals)
• Ceramic Capacitors can be utilized in devices and components to protect the sensitive components from voltage spikes
• Voltage regulation circuits ( due to its stabilizing impact)
• Flash photography and other pulse applications (for storing and releasing energy.

Read More:

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Things to Remember 

• A Ceramic Capacitor is a type of Capacitor that utilises ceramic or Porcelain discs as the dielectric material.
• It can have a capacitance in the range between 1nF to 1µF.
• Multi-layer ceramic capacitors (MLCC) and ceramic disc capacitors are the most significant Ceramic Capacitors in modern electronics. 
• Ceramic Capacitors are usually non-polarized and hence terminals can be connected to the circuit either way.
• The most common dielectric compounds used in Ceramic capacitors include titanium dioxide, Strontium Titanate, and Barium Titanate.
• The important features of Ceramic Capacitors are:-Large Capacitance, High Voltage Tolerance, Precision and accuracy, Small, compact size packaging 
• These are mostly used in:- Power supply Circuits, RF Circuits, Microwave Circuits, Audio/ Radio Frequency signals & electronic devices 

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