What Is A PCB?

Used in almost all electronic products, Printed Circuit Boards (PCB) route signals and power between various physical devices using conductive tracks, pads and other features. These are etched on copper sheets, which are then laminated onto a substrate.

PCBs came about as the need for a compact, cost-effective solution for the burgeoning electronics market grew. Replacing older methods prone to frequent short circuits and failures, nowadays PCBs are designed with dedicated layout software such as Altium or other CAD software, laying out the circuit to best suit the electronic product being developed.

The Structure Of A PCB


Usually made of fiberglass, though at times made of plastic, phenolic or epoxy, the substrate is what gives the PCB its rigidity.


A thin layer of copper foil is then laminated onto the substrate. This gives the PCB its Single-Sided, Double-Sided or Multi-Layer monicker, depending on the number of copper layers attached.


Single-sided PCBs have copper attached to just one side of the substrate, with copper traces on one side, and electrical parts and components on the other.


Double-Sided PCBs include copper and other parts and components on both sides of the substrate.


Often used in complex electronic circuits, multi-layer PCBs can have layers ranging in number from 4 to over 42, separated by insulation. The conductors on these layers are connected with plated through holes known as ‘Vias’.


The soldermask is what gives the PCB its common green colour that makes it so recognisable. This is used to insulate the copper layers underneath, protecting it from contact with other solders, conductive pieces and metals. This layer also has the solder points printed on it, acting much like a map to ensure soldering is carried out in the correct spots.


The final layer of the PCB is the silkscreen, applied to the soldermask. This adds important information like letters, numbers and symbols that aid in assembly. This layer also helps those who look at the board to understand its functions and connections, and are often referred to in the PCB’s design documents and manuals.

Frequent Asked Questions (FAQ) on Printed Circuit Boards

What are Printed Circuit Boards (PCB) used for?

Printed Circuit Boards (PCB) are used in a wide variety of electronic products, spanning the length and breadth of both the consumer and industrial electronics market. It’s here that they connect an array of both internal and external electronic and mechanical components through the use of conductive pathways, signal traces and tracks that are etched into copper sheets during the manufacturing process.

What is Circuit Board Design?

Circuit Board Design is the process by which Printed Circuit Boards (PCBs) are researched, prototyped, tested and then produced to fulfill the needs of a specific electronic project or product, all while ensuring the design is completed on time and within budget.

Almost every electronic product is made with one or more Printed Circuit Boards, each one varying in size, shape and configuration depending on the project in question, as well as any specific requirements or limitations, which will vary from project-to-project. Some may require more power, while others may need a smaller, miniaturised design for use in embedded or smaller products.

The design and creation process is usually kickstarted by determining the individual requirements of the PCB in question, and then follows on from there through a logical development process where the PCB is conceptualised, designed and then tested to ensure it performs to standard, fits within the desired dimensions and works with other circuits and connections as intended.

What is Circuit Board Manufacturing?

Circuit Board manufacturing Is the process through which a virtual PCB design is brought into the real world, and the initial concepts and CAD drawings are turned into a fully functional, real-world ready PCB. This process involves a number of important steps: from the initial feeding of this data to the PCB Computer Aided Manufacturing (CAM), through to Panelisation, Copper patterning, Lamination and Drilling, to name just a few.

Who built the first Circuit Board? And when was the Circuit Board invented?

Born in Vienna in 1907, Paul Eisler is heralded as the inventor of the world’s first Printed Circuit Board (PCB) in 1936. An inventor and engineer, Paul Eisler graduated from the Vienna University of Technology with an engineering degree, and was later awarded with both the Pour le Merite by the French government, as well as the Nuffield Silver medal from The Institute Of Electrical Engineering for his electronic ingenuity. Paul Eisler passed away on September 26th, 1992.

Why is a Circuit Board green?

Printed Circuit Boards (PCB) aren’t actually green. At least, not the entire thing. The green section that you see is actually the solder mask, which is laid on top of the board during the manufacturing process to both prevent short circuits and soldering errors. Why the solder mask is green is hotly debated, though many theorise that the resins that were melted down to create this layer in the earlier days of PCB manufacturing were green. Nowadays, however, circuit boards are no longer limited to just green. In fact, we can create boards with solder masks in any number of colours.

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