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What are Ceramic Capacitors?

Author: Apogeeweb Date: 8 Dec 2020  1231

capacitor definition

Introduction

Definition: A ceramic capacitor is a capacitor that has a ceramic dielectric as its dielectric material. Multi-layer ceramic capacitors and ceramic disc capacitors are the two most common types.

 

The dielectric in a ceramic capacitor is ceramic. Ceramics, a well-known insulator, is one of the first materials used in the manufacture of capacitors. Ceramic capacitors come in a variety of geometric forms, some of which have been phased out due to size, parasitic effects, or electrical characteristics, such as ceramic tubular capacitors and barrier layer capacitors. Multi-layer ceramic capacitor, also known as ceramic multi-layer chip capacitor (MLCC), and ceramic disc capacitor are the two types of ceramic capacitors most widely used in modern electronics.

                                                          Typical Multilayer Ceramic Capacitor

                                                                                   Typical Multilayer Ceramic Capacitor 

With a production volume of about 1000 billion devices per year, MLCCs are the most widely used capacitors. Due to their small size, they are commonly used and manufactured using SMD (surface-mounted) technology. Ceramic capacitors are usually made with very small capacitance levels, ranging from 1nF to 1F, with a maximum capacitance of 100F. Ceramic capacitors are thin, and their maximum rated voltage is low. Since they lack polarity, they can be safely linked to AC electricity.

 

Due to low parasitic effects including resistance and inductance, ceramic capacitors have excellent frequency response. Ceramic capacitors have the following advantages over other capacitors: small size, large capacity, good heat resistance, mass production suitability, and low price.

Catalog

Introduction

Catalog

ⅠThe Origin of Ceramic Capacitors

Ⅱ Classification of Ceramic Capacitors

  2.1 Semiconductor Ceramic Capacitors

  2.2 High Voltage Ceramic Capacitors

Ⅲ Characteristics

  3.1 Precision and Tolerance

  3.2 Size Advantages

  3.3 High Voltage and High Power

Ⅳ Ceramic Dielectric Types

Ⅴ Construction and Properties of Ceramic Capacitors

  5.1 Ceramic Disc Capacitors

  5.2 Multi-layer Ceramic Capacitor (MLCC)

Ⅵ Advantages and Disadvantages

  6.1 Advantages

  6.2 Disadvantages

Ⅶ Applications for Ceramic Capacitors

Ⅷ How to read ceramic capacitor value?

Ⅸ How to Test Ceramic Disc Capacitor

Ⅹ FAQ

The Origin of Ceramic Capacitors

Lombardi from Italy invented ceramic dielectric capacitors in 1900. It was discovered in the late 1930s that by adding titanate to ceramics, the dielectric constant can be doubled, resulting in cheaper ceramic dielectric capacitors.

 

Ceramic capacitors were first used in military electronic equipment around 1940, following the discovery of the insulation properties of BaTiO3 (Barium titanate), the primary raw material for today's ceramic capacitors. Around 1960, ceramic laminate capacitors became commercially available. It had become an essential part of electronic devices by 1970, thanks to the rapid growth of hybrid IC, computers, and portable electronic devices. Ceramic dielectric capacitors currently account for approximately 70% of the overall capacitor market.

                   Historic Ceramic Capacitors

                                                                                          Historic Ceramic Capacitors

Ⅱ Classification of Ceramic Capacitors

2.1 Semiconductor Ceramic Capacitors

(1)Surface Layer Ceramic Capacitor

The miniaturization of capacitors, that is, the capacitor obtains the largest possible capacity in the smallest possible volume, which is one of the development trends of capacitors. For the separation of capacitor components, there are two basic approaches to miniaturization:

①Make the dielectric constant of the dielectric material as high as possible;

②Make the thickness of the dielectric layer as thin as possible. Among ceramic materials, the dielectric constant of ferroelectric ceramics is very high, but when ferroelectric ceramics are used to manufacture ordinary ferroelectric ceramic capacitors, it is difficult to make the ceramic dielectric very thin. Firstly, due to the low strength of ferroelectric ceramics, it is difficult to carry out actual production operations because it is easy to fracture when it is thin. Secondly, when the ceramic medium is fragile, it is easy to cause various structural defects and the production process will be challenging.

(2)Grain Boundary Layer Ceramic Capacitor

The surface of BaTiO3 semiconductor ceramics with sufficiently developed grains is coated with appropriate metal oxides (such as CuO or Cu2O, MnO2, Bi2O3, Tl2O3, etc.), and heat treatment is performed under oxidizing conditions at appropriate temperatures. Then the substance will form a low eutectic solution phase with BaTiO3, rapidly diffuse and penetrate into the ceramic along with the open pores and grain boundaries, forming a thin solid solution insulating layer on the grain boundaries.

 

The resistivity of this thin solid solution insulating layer is very high (up to 1012~1013Ω·cm). Although the ceramic grain interior remains as semiconductor, the entire ceramic body is shown as the dielectric constant of 2×104 to 8×104 dielectric medium. Capacitors made with this kind of porcelain are called boundary layer ceramic capacitors, or BL capacitors for short.

2.2 High Voltage Ceramic Capacitors

The ceramic materials of high-voltage ceramic capacitors are barium titanate-based and strontium titanate-based. Barium titanate-based ceramic materials have the advantages of high dielectric coefficient and good AC withstand voltage characteristics, but also have the shortcomings of capacitance change rate with the increase of medium-temperature and decrease of insulation resistance. The Curie temperature of strontium titanate crystal is -250℃, and it is a cubic perovskite structure at room temperature.

 

It is a para-electric body, and there is no spontaneous polarization phenomenon. Under high voltage, the dielectric coefficient of strontium titanate ceramic material changes little. The dielectric loss tangent value (tgδ) and capacitance change rate are small, which makes it a high-voltage capacitor dielectric. 

2.3 Multilayer Ceramic Capacitors

Multilayer ceramic capacitors are the most widely used type of electronic component. They are stacked alternately in parallel with the internal electrode material and ceramic body and fired into a whole, also known as chip monolithic capacitors. It has the characteristic of small size, high specific volume and high precision. It can be mounted on a printed circuit board (PCB) and hybrid integrated circuit (HIC) substrates. It can effectively reduce the volume and weight of electronic information terminal products (especially portable products), and also improve product reliability.

                                                             MLCC

Multilayer ceramic capacitors conform to the IT industry's development direction of miniaturization, lightweight, high performance, and multifunction. The outline of the national vision goal for 2010 clearly puts forward that new components such as surface-mounted components should be the development focus of the electronic industry. It is not only simple packaging, good sealing, and can effectively isolate the opposite electrode. MLCC can store charge, block DC, filter merge, distinguish different frequencies and tune the circuit in the electronic circuit.

 

It can partially replace organic film capacitors and electrolytic capacitors in high-frequency switching power supplies, computer network power supplies and mobile communication equipment. What's more, it can greatly improve the filtering performance and anti-interference performance of high-frequency switching power supplies.                                                

Ⅲ Characteristics

3.1 Precision and Tolerance

Ceramic capacitors are currently available in two classes: class 1 and class 2. When high stability and low losses are needed, Class 1 ceramic capacitors are used. They are extremely precise, and the capacitance value remains constant regardless of applied voltage, temperature, or frequency. Within a total temperature range of -55 to +125 °C, the capacitance thermal stability of the NP0 series of capacitors is 0.54%. The nominal capacitance value's tolerances can be as poor as 1%.

 

Class 2 capacitors have a large capacitance per volume and are used in less sensitive applications. Their thermal stability in the operating temperature range is usually 15%, and nominal value tolerances are about 20%.

3.2 Size Advantages

MLCC devices outclass other capacitors when high component packing densities are needed, as is the case in most modern printed circuit boards (PCBs). The “0402 multi-layer ceramic capacitor package” measures just 0.4 mm x 0.2 mm to demonstrate this point. There are 500 or more ceramic and metal layers in such a box. As of 2010, the minimum ceramic thickness was on the order of 0.5 microns.

3.3 High Voltage and High Power

Ceramic capacitors that are physically bigger and can withstand even higher voltages are known as power ceramic capacitors. These are much larger than the ones used on PCBs, and they have specialized terminals for connecting to a high-voltage supply safely. Ceramic capacitors with a power specification of much more than 200 volt-amperes can withstand voltages ranging from 2 kV to 100 kV.

 

Printed circuit boards use smaller MLCCs that are rated for voltages ranging from a few volts to several hundreds of volts, depending on the application.

Ⅳ Ceramic Dielectric Types

Unlike other capacitor types such as tantalum capacitors and electrolytic capacitors, ceramic capacitors may use a variety of dielectrics. These various dielectrics give capacitors very different properties, so in addition to deciding on a ceramic capacitor, a second decision about the type of dielectric may be needed.

 

Popular ceramic capacitor dielectrics, such as C0G, NP0, X7R, Y5V, Z5U, and many others, are frequently listed in distributors' lists. However, determining which form is best necessitates a little more study.

 

Ceramic Capacitor Dielectric Classes

Some industry organizations have identified a range of ceramic dielectric application classes to make selecting capacitors with the appropriate dielectric easier. These application groups divide the various ceramic capacitor dielectrics into separate classes based on the anticipated application.

     Ceramic Capacitor Dielectric Classes

International bodies such as the IEC (International Electrotechnical Commission) and the EIA (Electronic Industries Alliance) have standardized these ceramic capacitor classes.

Ⅴ Construction and Properties of Ceramic Capacitors

5.1 Ceramic Disc Capacitors

Ceramic disc capacitors are made by coating a ceramic disc on both sides with silver contacts. These devices can be constructed from several layers to achieve higher capacitances. Ceramic disc capacitors are usually through-hole components that have lost popularity due to their large scale. If capacitance values allow, MLCCs are used instead. Ceramic disc capacitors have capacitance values ranging from 10pF to 100pF and voltage ratings ranging from 16 volts to 15 kV and beyond.

                                                                    High Voltage Ceramic Disc Capacitors

5.2 Multi-layer Ceramic Capacitor (MLCC)

MLCCs are made by combining finely ground granules of paraelectric and ferroelectric materials and layering the mixture with metal contacts alternately. Following the layering, the device is heated to a high temperature and the mixture sintered, yielding a ceramic substance with the desired properties. The capacitance of the resulting capacitor is increased by connecting several smaller capacitors in parallel. MLCCs are made up of 500 layers or more, with a minimum layer thickness of 0.5 microns. As technology advances, layer thickness decreases, allowing for higher capacitances in the same volume.


MLCC

Ⅵ Advantages and Disadvantages

6.1 Advantages

The following are some of the benefits of using a ceramic capacitor:

• This capacitor's physical structure is very compact.

• It is well suited for the application of AC signals due to its non-polarized nature.

• Signal interference suppression, such as radiofrequency suppression and electromagnetic interference suppression, is improved with these capacitors.

• This capacitor is reasonably priced, and it can withstand voltages of up to 100 volts.

6.2 Disadvantages

The following are the drawbacks of using these capacitors:

• The capacitance value of these capacitors is less than one microfarad.

• These components are also responsible for the Microphonic effect in circuits.

• It is unable to withstand high voltages. Since it can easily impact the dielectric present in it. As a consequence, there is a breakdown.

Ⅶ Applications for Ceramic Capacitors

Given that MLCCs are the most commonly manufactured capacitor in the electronics industry, it should come as no surprise that they have a wide range of applications. A resonant circuit in transmitter stations is an interesting high-precision, high-power application. High-voltage laser power supplies, power circuit breakers, and induction furnaces all use Class 2 high-power capacitors. Small-form SMD (surface mount) capacitors are commonly used in printed circuit boards, and capacitors the size of a grain of sand are used in high-density applications.

 

They're also used in DC-DC converters, where high frequencies and high levels of electrical noise put a lot of strain on the components. Since ceramic capacitors are non-polarized and come in a wide range of capacitances, voltage ratings, and sizes, they can be used as a general-purpose capacitor. Ceramic disc capacitors, which are used throughout brush DC motors to reduce RF noise, are familiar to many hobbyists, especially in the field of robotics.

Ⅷ How to read ceramic capacitor value?

Ceramic capacitors normally have three digits for their values, such as 102, 103, and 101, and the values are in Pico farads. The numbering scheme is simple to understand if you note that picofarads, not microfarads, are used.

The worth of a ceramic capacitor with three digits – ABC is AB*10^C Pico Farad. The digit 104 means 10*104pF = 100000pF = 100nF = 0.1uF if ABC is 104. The first two digits of the printed code correspond to the first two digits of the capacitor value, while the third digit indicates the number of zeroes that must be applied to convert the capacitor value to Pico Farad.

 

If we calculate in Nano Farad for values ending with 4, then the reading becomes easy like 104 is 100nF. 

If we calculate in Nano Farad for values ending with 3, then the reading becomes easy like 103 is 10nF.How to read ceramic capacitor value

Some ceramic capacitors are polarized, meaning they have both positive and negative terminals. The capacitor can be identified by its tolerance in addition to its capacitance value. There is many tolerance marking schemes in use, with one and two alphabets being the most common. You don't need to recall them unless you're dealing with a precise circuit.

 

We only looked at ceramic capacitors in direct current (DC) circuits with voltages ranging from 12V to near zero in this short article. Hobbyists are familiar with this collection. It is also useful to be familiar with the tolerance marking scheme for professional purposes.

 

Ⅸ How to Test Ceramic Disc Capacitor

Ceramic disc capacitors are units used in the computer industry to control voltage for various dielectric functions. Ceramic layers aim to dissipate heat generated by high voltage while also protecting the environment — both internal and external — from damage. Volumetric efficiency is inversely proportional to stability and accuracy with these capacitors, making testing difficult.

Step 1

Ceramic capacitors must be tested since they will short out if they are exposed to high voltage. Your monitor can blink or go blank if this happens. This issue can be resolved by removing all of the ceramic capacitors. Ceramic capacitors, on the other hand, can be tested if you have the right tools.

 

Step 2

To measure a ceramic capacitor, use a wireless multimeter. The capacitor works properly when the voltage is constant. However, you won't be able to accurately calculate it if the ohmmeter's output and digital capacitance don't match the capacitor's voltage, so the second option is preferable.

 

Step 3

To locate the short circuit or assess cases where optical capacitance meters fail to produce shortened readings, use an analog insulation tester. In order to obtain a 12-volt output, set the analog meter to 10 Kohm. This phase is needed for the ceramic capacitor to be tested. You may also use both methods to improve measurement precision if you do want to stop removing the capacitor and test it aboard.

Related recommendation: How to Test a Start Capacitor?

                                             How to Discharge a Capacitor?

 

Ⅹ FAQ

1. What is Ceramic Capacitor?

A fixed value type of capacitor where the ceramic material within the capacitor acts as a dielectric is the Ceramic Capacitor. This capacitor consists of more alternating layers with ceramic and also a metal layer which acts as an electrode. The composition of this ceramic material in this capacitor tells about the electrical behavior along with its applications. We can define a ceramic capacitor as A fixed-value capacitor where the ceramic material acts as the dielectric.

 

2. What are the advantages of ceramic capacitors?

Following are the advantages of ceramic capacitors:

  • Manufacturing cost is less
  • High-frequency performance is exhibited
  • The stability of the capacitor is dependent on the ceramic dielectric

 

3. What is the capacitance range for a ceramic capacitor?

The typical capacitance range for a ceramic capacitor is 10 pF to 0.1 μF.

 

4. Can I replace all electrolytic capacitors with ceramic ones?

If you can find ceramic capacitors of the correct value, you can certainly do this. Ceramic capacitors are more stable, have a longer useful lifetime, have higher voltage ratings and are not polarized. Be prepared to find that there will be a substantial size difference.

 

5. What are the differences between electrolytic, tantalum and ceramic capacitors?

Ceramic capacitors don't have polarity, their terminals can be interchanged. They are suitable for both ac and dc. They don't have any chemical reaction involved in their work. They have a lesser capacity for the same given size.

 

Electrolytic capacitors have polarity (i.e. they have fixed positive and negative terminal), Suitable for dc only. A chemical reaction involves the formation of aluminum oxide on the electrode. ( Consists of aluminum electrodes in a solution of Ammonium borate).Higher capacity.

 

A tantalum electrolytic capacitor, a member of the family of electrolytic capacitors, is a polarized capacitor whose anode electrode (+) is made of tantalum on which a very thin insulating oxide layer is formed, which acts as the dielectric of the capacitor. A solid or liquid electrolyte that covers the surface of the oxide layer serves as the second electrode (cathode) (-) of the capacitor.

 

6. What is the time constant for the discharge of the capacitors in (figure 1)?

FAQ-time constantfigure 1

The equivalent resistance:

R= 2*1× 10∧3 = 2000 i©

=> the time constant: T= R*C = 2000*1× 10∧-6 = 2×10∧-3s = 2ms

 

Ordering & Quality

Photo Mfr. Part # Company Description Package PDF Qty Pricing
(USD)
EEU-FC1J101 EEU-FC1J101 Company:Panasonic Remark:Aluminum Electrolytic Capacitors - Radial Leaded 100uF 63V Package:N/A
N/A
In Stock:On Order
Inquiry
Price:
1+: $0.51000
10+: $0.39000
2500+: $0.13200
Inquiry
T491X476K035AT T491X476K035AT Company:KEMET Remark:Tantalum Capacitors - Solid SMD 35V 47uF 2917 10% ESR=600mOhms Package:N/A
N/A
In Stock:On Order
Inquiry
Price:
1+: $2.65000
10+: $2.05000
100+: $1.62000
500+: $1.08000
1000+: $0.96900
2500+: $0.90000
10000+: $0.86500
Inquiry
T491B476K010AT T491B476K010AT Company:KEMET Remark:Tantalum Capacitors - Solid SMD 10V 47UF 1311 10% ESR=1 Ohms Package:N/A
N/A
In Stock:On Order
Inquiry
Price:
1+: $0.57000
10+: $0.31300
100+: $0.22000
500+: $0.20200
1000+: $0.17200
2000+: $0.13700
10000+: $0.13300
24000+: $0.12900
50000+: $0.12500
Inquiry
C0603X104K5RACTU C0603X104K5RACTU Company:KEMET Remark:Multilayer Ceramic Capacitors MLCC - SMD/SMT 50V 0.1uF 0603 X7R 0.1 Package:N/A
N/A
In Stock:On Order
Inquiry
Price:
1+: $0.19000
10+: $0.07700
100+: $0.06500
500+: $0.04400
1000+: $0.03900
4000+: $0.03300
8000+: $0.02900
24000+: $0.02800
48000+: $0.02700
Inquiry

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