Printed circuit boards (PCBs) are essential for modern-day life, but learning the ins and outs of what is often a complicated subject can be intimidating.  Our PCB for beginners guide helps you understand the basics of printed circuit boards, so you will be more familiar with components and materials should you decide to design your own custom printed circuit boards for a prototype or new product.

What is a Printed Circuit Board (PCB)?

A printed circuit board, commonly called a “PCB,” is a (usually) rigid board printed with electrical circuitry called traces.  Components and layers can then be added to engineer and build a nearly limitless array of designs fulfilling most any need.  While the fundamentals of printed circuit boards seem simple at first, once you begin to design your own circuit boards the complexities are noticed quickly.

PCB Basics: Terminologies

Soldermask

A layer of protection for leads that prevents oxidation and sometimes acts as a safeguard against solder bridges and shorts when solder pads and/or traces are especially close together.

Silkscreen

The silkscreen layer is typically white, but can be other colors, and serves as a reference guide and sometimes contains decorative graphics.

Pads

Pads are areas on the printed circuit board that have exposed metal in order to connect components to the PCB.  Typically, solder is used to adhere items to the surface of the pad, but there are many choices for both pad design and methods of establishing connections.

Layers

In printed circuit boards, you will hear the term “layers” quite a bit.  While you may hear a PCB being referred to as a “single layer PCB” and think of it in terms as  in reality, even a single layer PCB contains multiple layers of material in order to operate correctly.  These can be 2 layer PCB, 4 layer PCB, and so forth.  Typically, when a printed circuit board is referred to as having a certain number of layers, they are counting the number of conducting patterns.

Footprint

The footprint of a printed circuit board is the blueprint of where the components will be attached to the board itself, including where the pads and through-holes should be located.

Jumper

Jumpers are typically pins, either insulated or non-insulated, used as conductors.  They may be incorporated into a PCB design either due to minimizing PCB costs by reducing the number of traces and/or layers in a board design, or to make a PCB that can be configured multiple ways by cutting certain jumpers.  Jumpers used to be used regularly in PCB design, but are less common in modern PCBs.

Via or Thru-hole Via

A via is a plated hole wall that goes through part of the printed circuit board to provide a path that can connect the electrical signal from one layer to another.  There are different types of vias, but the most common type of via, called a thru-hole via, is a hole that goes from the top of the PCB all the way through to the bottom.

Blind Via

A blind via is very similar to a thru-hole via, but the hole stops at some point, and does not extend all the way through the printed circuit board.  Since blind vias are closed at one end, the plating process can be more difficult, which means increased costs.

Buried Via

Buried vias are contained within an internal structure, and do not have an external opening.  Since buried vias are laminated over, it saves space and allows for more elements to be added to the external layers.  When creating small PCBs, there often wouldn’t be enough room to add components if one were to use a thru-hole via.

Copper Traces

The copper traces on a printed circuit board act in a similar way to wire.  When a PCB is created, a thin layer of copper is attached to the board, and the pattern of the traces is overlaid with an etch-resistant coating.  This allows the rest of the copper to be removed from the board.  The copper traces on PCBs are more precise and much faster to create than traditional wiring.

Annular Ring

An annular ring is the ring of copper that encircles a via.  Annular rings are important because they serve as the point of contact for the connections between layers on a PCB.  Vias created for this purpose are typically larger than other types of vias, and the diameter of annular rings can have an effect on your overall design.

Design rule check (DRC)

When you are designing your printed circuit board, you will run design rule checks (DRCs) regularly while creating your layouts and schematics.  A design rule check makes sure that your design fits the parameters set for the manufacturing process.

Gerber file

Gerber files are the industry standard format for PCB manufacturing.  You will save your PCB design as a Gerber file to give to your manufacturer so that your printed circuit boards can go into production.

PCB: Classification

Printed circuit boards are classified in any number of ways, depending on the design, utilization, and other features.  Just a few of the many ways to classify printed circuit boards