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PCB dielectric constant – the ability to store electrical energy


PCB dielectric constant is a property that describes the ability of the PCB materials to store electrical energy. A high dielectric constant means that the material has good storing abilities, whereas a low value indicates that it has poor storing abilities. For example, if you have two different materials with dielectrics having different values and apply DC voltage across them, then we can say that one is better than another in terms of storing energy (dielectric strength).

The dielectric constant is important in the design of PCB because PCB dielectric constant affects how much power can be stored on the board, which determines how long your circuit will last before it needs replacement. The higher the dielectric constant of a material, the more energy it can hold per unit area.

How is PCB dielectric constant calculated?

When you design a PCB, it’s important to know how to calculate the dielectric constant of the material. The PCB dielectric constant material affects the capacitance value in the board design. The higher the dielectric constant , the more capacitance per unit area. This means that if you want more capacitance per mm2 or per square inch, then your PCB must have higher dielectric constant values than those specified by PCB makers or suppliers.

The PCB dielectric constant of an insulator or semiconductor is calculated by dividing its permittivity by its permeability in free space and it is measured in units of capacitance per unit volume, called farads per cubic meter (F/m3).

Why is the PCB dielectric constant so important?

PCB dielectric constant is so important in many aspects. It is a material property that varies from material to material and also with temperature. It’s important to understand this concept because it will help you predict the properties of materials, especially when working with them in high-frequency applications.

The PCB dielectric constant material affects the capacitance value in the board design. This means that a high-dielectric-constant circuit will have a lower overall resistance than a low-dielectric-constant circuit and therefore be more efficient at transferring energy from one place to another.

On the other hand, if you want to make sure that your circuit doesn’t lose too much power when it’s not being used (for example, because there’s no load on it), then you want as little capacitance as possible—and this means choosing components with low values of dielectric constant.

High-frequency operation requires low dielectric constant materials, whereas low-frequency operation requires high-dielectric constant materials. In addition, high power density means higher currents flowing through wires or traces; these currents will be faster if they’re conducted by low-loss materials with low dielectrics constants like aluminum and copper. Low power density means less current flowing; therefore, there will be less heat generated when conducting electricity over long distances so you’ll need less insulation between your components!


What is dielectric material?

Due to the absence of free electrons which is responsible to conduct electric current through the substance, dielectric materials are bad conductors of electricity. It has a high power of resistance, and the capacity to hold electrical charges.

In order to function as dielectric materials instead of conductors, dielectric materials allow dielectric polarity. When it is exposed to an electromagnetic field, this phenomenon happens when positive particles are shifted in the electric field’s plane and negative particles are moved in the opposite way. This polarity generates a potent inner field that weakens the material’s net electric field.

Types of dielectric materials

Dielectric materials can be divided into two types: homogeneous and heterogeneous.

★In the case of homogeneous materials, there is one type of polar molecule present in its structure; these molecules may or may not be present at the same time depending on their concentration. The homogeneous dielectric material has the same properties in all directions, which means it is easy to apply electric current. However, its heat resistance is weak due to its high dielectric constant value.

★On the other hand, heterogeneous dielectrics have different properties in different directions; therefore they can be used for blocking electrical waves or noise effectively when placed on a circuit board with transmission lines. The AC resistance increases as we move away from terminals (positive terminal) while it decreases as we move closer toward them (negative terminal).

What is FR4 dielectric constant?

The most common kind of PCB composite is FR4, and it has an excellent material characteristics. FR4’s dielectric constant varies in the range between 3.8 to 4.8 dependent on the type of glass weaving, density, resin material, and texture of the copper layer.

How can reduce the dielectric constant in PCB?

The PCB dielectric constant material can be reduced by adding filler materials like glass fibers or ceramic powders in resin systems. PCBs are typically made of plastic, which has a high dielectric constant. PCBs can be made of other materials with a lower dielectric constant, which can improve their performance. ●Materials with a low dielectric constant

1. Alumina

2. Metal

3. Ceramic

●Methods for reducing dielectric constant

1. Changing the material used

2. Controlling the temperature

3. Controlling the humidity

4. By altering the manufacturing process

5. By applying a dielectric coating to the PCB

If you’re looking to improve the performance of your PCBs, consider using materials with a lower dielectric constant.


Dielectric constant is a very important parameter in PCB design, and PCB dielectric constant has been used to describe the electrical characteristics of materials. It’s important because it affects the capacitance and conductance (i.e., how easily electrons can flow through) of that material as well as its overall dielectric loss (losses due to internal resistance).

If you are using a PCB with low or high dielectric constant, it will affect your signal and could affect performance. In short, dielectric constant is a very important factor in the design of PCBs.



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