Types of PCB Boards: Ultimate Reference with Specs & Use Cases

A printed circuit board (PCB) consists of laminated insulating and conductive materials that connect multiple electrical devices. A PCB can be thought of as a layered composite of fibreglass and epoxy with copper patterns etched onto it. These serve as electrical conductors and pathways for signals and power. A PCB can be Simple (one layer of conductive material), Double-Sided (two conductive layers), or Complex (three or more conductive layers) to allow numerous circuit paths on a small piece of hardware. According to IPC, a PCB consists of conductive and non-conductive materials that have been laminated together to form an electrical circuit for an electrical assembly.

Official IPC Definition + Layer Anatomy

The practical definition is clear: a PCB consists of alternating dielectric and metal copper foil layers. The copper layers have patterns of traces, planes, pads, and vias that connect components. A typical 4-layer PCB stack‑up might look like:

Copper layer – Prepreg or core – Copper – Core – Copper

All layers are bonded together. The resin/glass substrate gives mechanical strength and electrical insulation. IPC-2221 and IPC-4101 standards govern stack‑up geometry and material properties. But for our purposes, think of a PCB as a multilayer sandwich board where copper slices (traces) carry electrons instead of cheese.

12 Core Types of PCB Boards (2025 Edition)

Engineers typically sort PCBs by construction and purpose. Here are 12 fundamental PCB types you’ll encounter in 2025:

Single-Sided / Double-Sided / Multilayer

• Single-panel PCB: It has only a copper circuit layer. This is the most basic type of PCB, as it is inexpensive to produce. It is used in basic consumer electronics that have a low circuit density, for example, components and traces are located on just one side of the board.

• Double-panel PCB: The circuit layer is made of copper on both sides of the board. This allows for more complex routing because there are vias connecting the two surfaces together. Most often, this type of PCB is found in audio systems and power supplies.

• Multilayer PCB: They consist of at least three copper circuit layers, with insulating layers separating the conductive layers.There are insulating materials that separate the copper circuit layers. Multilayer boards are used in devices that require multiple layers of circuits to work properly, like mobile phones. Multilayer boards also often have ground and power planes that provide noise reduction.

Rigid / Flexible / Rigid-Flex

• Rigid PCB: The classic FR-4 board you know. It’s stiff and flat. Rigid PCBs dominate the boards of every device, from computers and TVs to industrial controllers. They offer excellent component support and are low-cost.

• Flexible PCB (Flex): Made of bendable plastic substrates. These can bend and are ideal for compact or dynamic designs. Popular in automotive and medical devices that require flexing or unusual shapes.

• Rigid-Flex PCB: Combines rigid boards with flexible tails. We can think of sections of FR-4 connected by flex material. Used in high-reliability gear where part of the circuit needs to move or fold. Rigid-flex boards save space and improve reliability over using cables to connect boards.

Metal-Core / HDI / High-Frequency / Ceramic / Thick-Copper

• Metal-Core PCB (MCPCB): Also called Insulated Metal Substrate. These have a metal core, usually aluminium and are bonded under the dielectric. The metal with high thermal conductivity acts like a heatsink. It spreads heat from power components.

• High-Density Interconnect (HDI) PCB: Ultra-fine circuitry boards. HDI boards have minimal features containing microvias (often laser-drilled), very thin traces, and high component density. They are required when BGA chips or 0.4mm-pitch parts are used. HDI allows stacking vias-in-pad and more layers in a small area.

• High-Frequency PCB: Specialized laminates like Rogers and PTFE are used for high-speed signals. These boards came with low dielectric loss and a stable dielectric constant (Dk). They are found in RF systems and Wi-Fi routers.

• Ceramic PCB: Uses ceramic (alumina or AlN) as the substrate instead of FR-4. Ceramics have excellent thermal and high-frequency properties. They’re rigid and heat-resistant. Ceramic PCBs appear in speciality fields like high-power LED modules.

• Thick-Copper PCB: Standard FR4 PCBs usually have 1oz copper (35µm thick) per layer. Thick copper boards contain significantly more copper (3–20 oz or more). The extra thickness boosts current capacity and thermal mass. They are ideal for power electronics and charging systems. For example, heavy-copper PCBs can carry 30 amps or more without frying the traces.

Types of Circuit Boards by Real-World Applications:

Different industries favour different PCB types and materials. Here are broad application categories and what boards they typically use:

• Consumer & Mobile: Smartphones, tablets, laptops and smart TVs.These rely heavily on rigid multilayer HDI boards, thanks to miniaturisation and high performance. Modern smartphones use an eight-layer HDI stack-up to pack processing.

• Automotive & EV: Modern cars and EVs are loaded with electronics. Underhood and powertrain modules often use rigid multicore PCBs with heavy copper. Automotive boards are usually made to IPC Class 2 or 3 standards.  All this is to keep these boards stable under vibration and temperature resilience.

• Medical: Medical devices and Implantables like pacemakers often need HDI and flex PCBs for ultra-compact form factors. Diagnostic machines use rigid multilayer boards with high reliability. In many cases, medical PCBs must meet IPC Class 3 standards and comply with UL 94V-0.

• Aerospace & Defense: This is the ultimate no-fail environment. Boards here often must withstand extreme conditions (temperature swings, vibration, radiation) and have zero tolerance for failure. You’ll find high-frequency laminates (Rogers, PTFE) and ceramic PCBs in radar, satellite, and RF comms; often, every board is Class 3-level quality.

PCB Components That Force Specific Board Types:

Specific components or design needs dictate your PCB type. Key examples:

BGA & Fine-Pitch Components → HDI PCBs:

Modern chips, such as BGAs (Ball Grid Arrays), have tiny pads that must be routed with microvias and ultra-fine traces. Achieving their breakouts usually requires HDI techniques. In practice, they are used if you have a 0.5mm‑pitch BGA or a multi-gigabit processor.

High Current → Thick-Copper / Metal-Core PCBs:

Any design where amps are in double digits needs extra copper to carry current without burning up. Heavy-copper PCBs or metal-core boards become necessary. The thick copper adds cross-sectional area for current and also helps spread heat. If you’re designing a 30A motor controller, a standard 1oz FR4 won’t cut it, and you need a heavy-copper or MCPCB build.

High Voltage → Special High-Dielectric Materials:

When circuits operate at high voltage, some hundred volts and above, insulation and clearance become critical. Standard FR-4 has good dielectric strength (20–80 kV/mm), but for very high-voltage PCBs, designers may choose materials with even higher breakdown voltages. They also increase creepage/clearance distances. In essence, designing for high voltage means picking board materials and spacings with very high dielectric strength.

Must-Know PCB Standards & Classes

Every serious PCB engineer must know the major specs:

IPC-6012D (IPC-6012DS) Class 2 vs Class 3:

IPC is the standard for assessing the quality of bare printed circuit boards. Class 2 boards are designated for dedicated service and various consumer and commercial product applications. IPC class 2 allows for certain minor defect types, but expects skilled workmanship to be evident on these types of boards.

For products that are considered critical/used for critical life support, such as aerospace computer systems and similar types of applications, IPC 6012 class 3 boards have the most stringent fabrication tolerances, the cleanest finished product and the highest reliability requirements. An example of a class 2 product is a smartphone PCB, whereas an example of a class 3 product is an aircraft control computer.

UL 94V-0, IPC-4101, RoHS 3 and MIL-PRF-31032 :

UL 94V-0 Flammability: UL 94 is a plastics flammability standard. V-0 is the most flame-retardant rating for PCBs. It means that when the board material is tested vertically, any burning stops within 10 seconds with no flaming drips. Virtually all FR‑4 boards aim for UL 94V‑0.

IPC-4101: This standard contains specifications for base laminate materials. Specifically, it outlines the characteristics of substrates, prepreg, and cores. Designers look to the grades within IPC-4101 to help them choose materials. The standard FR4 (TG130/140) is mentioned in 4101, which tells us that it has specific characteristics in terms of dielectric and thermal values.

RoHS 3: This refers to the Restriction of Hazardous Substances and is an EU directive (European Union). They have placed a ban on additional toxins/poisons, including lead, mercury, cadmium, etc, that may be associated with electronic devices. RoHS 3 is the most recent update that added a few different substances. This means that your PCB manufacturer is going to be eliminating flame retardants that are hazardous.

Emerging & Niche PCB Types to Watch

The PCB world keeps evolving. A few cutting-edge trends to keep an eye on:

Embedded Passive Components: Embedded passive boards utilise layer circuitry instead of surface-mounted components. Instead of soldering a (resistor) surface mount component with a 100 ohm value, a resistive trace could be printed within the layers of the embedded passive board. The benefit of an embedded passive board includes fewer parts, a smaller overall size and better performance with high-speed signals.

Additive 3D Printed Board Fabrication: 3D printed PCBs can be built through adding multiple layers of material from a 3D printer by depositing material layer by layer. This technology is not yet in mass production, but it represents an enormous advantage for designers in the ability to quickly create and test prototypes within a few hours of creating CAD files. 3D printed PCBs also allow the designer to create complex geometries that would typically be difficult or impossible to etch and drill.

Environmentally Friendly and Sustainable PCB Manufacturing: PCB designs are now designed to address the need for environmentally friendly products by developing new methods of environmentally friendly and sustainable PCB manufacturing.  For instance, PCB manufacturers are developing flexible PCB designs made from bio-based polymers. Examples of bio-based polymers include: Cellulose and those polymers that can be degradably disposed of; these types will allow for lower amounts of electronic waste resulting from plastics being disposed of.

Conclusion

In sum, not all PCBs are created equal. They come in many flavours. From single-layer FR‑4 boards in your toys, to multilayer HDI in smartphones, to metal-core power boards in electric vehicles. Each type serves its own purpose. Whether you’re fitting dozens of chips under a tiny phone screen or routing tens of amps through an EV inverter, there is a PCB built for the job.

Curious to see these boards in action? Check out JLCPCB’s resources. The HDI guide, heavy copper overview, and flex PCB guide offer practical examples. When you're ready to turn your design into a board, JLCPCB can fabricate virtually any of these PCBs.