A Quick Guide to Different Types of Printed Circuit Boards

The Printed Circuit Boards (PCB) are widely used in various equipment across industries such as automobile, telecommunication, aerospace, military, healthcare, etc. Therefore, the PCBs are manufactured and supplied based on the purpose of various applications. These printed circuit boards (PCBs) can be distinguished based on various parameters. This two-part post provides insights on different types of printed circuit boards (PCBs).

Know About the Different Types of PCBs

boards can be differentiated in different ways, however, the following categorizations stand out:

  • Substrate-based categorization: Depending on the use of substrates, the printed circuit boards (PCBs) are differentiated as rigid, flex, and rigid-flex PCBs.
  • Layer-based categorization: Based on the number of layers, the printed circuit boards are differentiated as single-layer/one-sided PCB, double layer/ double-sided PCB and Multi-layer PCBs.
  • Material-based categorization: Depending on the material used for construction, the PCBs can be differentiated as FR4 PCBs and metal core PCBs.

An Overview of the Different Types of PCBs Based on Substrates

The substrate-based characterization mainly focuses on three types of printed circuit boards (PCBs), which are described as below:

  • Rigid PCBs: Rigid PCBs are manufactured using a solid material substrate. This solid substrate keeps the rigid PCB from twisting or bending. These are probably the most common and highly manufactured types of PCBs. The number of layers is not a constraint for this type of printed circuit boards, it can be single-layered and 10-layered as well. Fiberglass is the common manufacturing material that is used for manufacturing rigid PCBs. It offers the benefit of security, as it keeps the mounted components intact at the position since it resists twisting. A computer motherboard is the most common example of this type of PCB.
  • Flex PCBs: Unlike, rigid PCBs, the flex PCBs are manufactured from flexible substrates, thus the name. It can be manufactured in single, double or multiple layers with flexible backing. The biggest advantage of these flex PCBs is that it is flexible. It can be wrapped or folded according to the convenience of the application. Being made of flexible substrates, these PCBs are waterproof, corrosion-resistant, and temperature-efficient. They are ideal for applications that demand high bending and flexing. The flexible PCBs have gained immense popularity over the years owing to their flexible nature and compatibility with any type of components or connectors.
  • The most common applications of flex PCBs is in portable electronics, desktop printers, hard disk drives, etc.

  • Rigid-Flex PCBs: Rigid-flex PCB is a combination of the above-discussed types of PCBs. These circuit boards are fabricated by layering the flexible conductive layers over a rigid PCB. The benefit of this type of PCB is that it offers a streamlined design and reduces the weight and size of the PCB. Like flexible PCBs, these rigid-flexible PCBs can also withstand high temperatures and harsh working environments.

The common applications of these rigid-flex PCBs are digital cameras, automobiles, cellphones, pacemakers, etc.

The printed circuit boards are referred in different ways depending on their designs, constructions, materials, and so on. The previous post focused on different types of printed circuit boards based on substrates. Here the focus is on layer-based and material-based PCBs. These two are important categories of PCBs since the majority of application-oriented PCB manufacturing involves these types.

What Are The Different Types of PCBs Based on Layers?

The layer-based differentiation takes into account the number of layers on the PCB. The combination conductor film and prepreg create a laminate/chapter, and the number of laminates creates a book. Therefore, the number of chapters or layers in the PCB decides the type of layer-based PCBs.

  • Single-layer or single-sided PCBs: The single layer PCBs are made of only one layer of the material substrate. The layer of substrate or core material is coated with a thin film of conductive material. Generally, the conductive layer is of copper (Cu) film. Finally, the copper layer is coated with a silkscreen to mark the components on the board. This is the simplest form of PCBs which is generally manufactured for DIY applications and for prototypes. The common application of single-layer PCBs is in radio equipment, LEDs, etc.
  • Double-layer or double-sided PCBs: The double-layer PCBs are fabricated by layering the laminates of a substrate with a conductive material, one over another. The holes are drilled through the layers to achieve through-hole PCB assembly. The small wires called leads are driven through the holes and then are soldered to the appropriate components. It offers the benefit of connecting the circuits or the components in two ways such as surface mount or through-hole connections.
  • Although in the surface mount there is no need for wire connections, the double-layer board itself is used as a wiring surface for components. The common applications of double-layer PCBs are vending machines, lighting systems, car dashboards, and amplifiers, etc.
  • Multi-layer PCBs: Multi-layer PCBs are further advancement of double-layer PCBs. Similar to double-layer PCB, multiple layers are added on both sides of the core. This allows the PCB designers and manufacturers to develop complex and thick PCBs. The benefit of multi-layer PCBs is that there is less amount of electromagnetic interference and it offers equivalent power distribution. This results in minimum connection wire damage.

These PCBs are used in complex devices like computers, heart monitors, interactive displays, automobiles, etc.

An Overview of the Different Types of PCBs Based on Material

According to the requirements at the end of the application, the PCBs are developed in different material compositions. The following are the types of printed circuit boards according to material-based categorization.

  • FR4 PCBs: The FR4 PCBs are constructed for the applications where fire-resistance is important. In FR4, the term FR signifies flame retardant and 4 signifies the woven glass fibers with epoxy resins. These PCBs are made of glass fibers and epoxy resins which makes it self-fire-resistant. Owing to several economic and mechanical benefits, this is the most common type of PCB in use today.
  • Metal Core PCBs: The material substrates used in these metal core PCBs are aluminum, copper and steel alloy. For varying purposes like good heat dissipation, aluminum is used where for lower thermal conductivity steel alloys are used. These PCBs can be made into any number of layers of any substrate-based form. The application of metal core PCBs is extensive in LED systems and modern electronics.

Both FR4 and metal core PCBs can be designed as a single layer, double-layer or multi-layered PCBs or rigid-flex PCBs depending on the application requirements. As the types of printed circuit boards are introduced well, it is important to choose the manufacturer or suppliers wisely. Since PCBs are highly important parts of industrial applications, you should purchase the trusted manufacturers like Rigiflex Technology, Inc. The company has been providing rigid, flexible, and rigid-flexible PCBs for its clients across industries like medical, aeronautics, telecom, networking and communication for several years now.