The Basics of Printed Circuit Boards: A Beginner-Friendly Guide

If you went around your house and collected all of your electronic devices and took them apart, there would be one thing in common: one of their central components would be a printed circuit board (PCB). 

PCBs are not just in household electronics. They are also a significant part of many different types of medical equipment, planes, spaceships, and more. PCBs mainly provide electrical connection and mechanical support to a circuit’s electrical components.

Before PCBs were around, electronics used to require circuits that were constructed via a challenging and time-consuming point-to-point wiring process, which often resulted in failures at wire junctions and short circuits as the wires of this circuit aged and cracked. 

However, as electronics transitioned from vacuum tubes and relays to silicon and integrated circuits and became more prevalent in consumer goods, their demand to become smaller and more cost-effective increased. It is why the PCB came into the picture and why PCBs have continued to shrink in size ever since.

What is a printed circuit board composed of? 

In many ways, a PCB can be compared to a multilayered cake, as it is made out of alternating layers of different materials that are laminated to form a single object. The following are the primary materials that most PCBs are composed of:

Substrate (FR4)

A PCB’s substrate is its base material and contains fibreglass (designated as FR4 in most cases). This solid fibreglass core gives a PCB its rigidity and thickness, although PCBs can come in various thicknesses, ranging from 0.2 mm to about 6.1 mm. Some cheaper PCBs have substrates made of less expensive (and less durable) materials, such as epoxies or phenolics.

Copper

The next layer of a PCB is a thin copper foil laminated to the board with heat and adhesive. While cheaper electronics tend only to have this copper on one side of the PCB, it is common for double-sided PCBs to have copper applied to both sides of the substrate. The number of copper layers can vary, ranging from just one to upwards of 16. 

Solder Mask

On top of the copper layer is the solder mask layer, which is generally green. The solder mask is overlaid onto the copper layer to insulate the copper traces and prevent accidental contact between them and other metal, solder, or conductive bits. 

The solder mask generally covers most of the PCB, leaving only silver rings and SMD pads exposed so they can be soldered. It makes it easier to solder to the correct places and prevents solder jumpers. 

Silkscreen

A silkscreen layer is applied on top of the solder mask layer, which adds letters, numbers, and symbols to the PCB that indicate where various parts are to make assembly easier. These labels also often indicate the function of each pin or LED. White silkscreen is usually used, but other colours can also be utilized. 

What are the different types of printed circuit boards?

Several different types of PCBs exist, and the differences that exist between these PCBs make certain ones better suited for specific types of applications. The following are the most common types of PCBs:

Single Layer PCBs

A single-layer PCB, or a single-sided PCB, is the simplest type of PCB and is widely used because it is easier to design and manufacture. This kind of PCB only has one side coated with a conducting material like copper, meaning only one side of the PCB is used to connect electrical or electronic components. 

These PCBs are often used in low-cost products manufactured in bulk, such as calculators, printers, and radios.

Double Layer PCBs

A double-layer PCB, also known as a double-sided PCB, has a thin layer of conducting material like copper applied to both the top and bottom of the board. These boards tend to be more flexible and relatively low cost, but their most significant advantage is that they have a reduced size that makes the circuit compact. 

Double-layer PCBs are generally used in industrial controls, UPS systems, converters, HVAC applications, power monitoring systems, phones, and amplifiers. 

Multilayer PCBs

Multilayer PCBs have at least conductive layers of copper. Board glue is sandwiched between the insulation layers to ensure excess heat does not damage any of the circuit’s components. This kind of PCB requires more complex designs and tends to be used when a device with limited space requires more significant electrical tasks. Multilayer PCBs include GPS technology, satellite systems, file servers, data storage, and medical equipment. 

Flexible PCBs

Instead of a solid and rigid substrate, flexible PCBs use a flexible plastic material, such as polyamide, polyether ether ketone, or transparent conductive polyester film, so that the circuit board can be bent, folded, or twisted, giving them improved resistance to vibrations and movement. Flexible PCBs are found in LCD fabrication, organic light-emitting diodes, flex solar cells, automobiles, cell phones, cameras, and laptops. 

How Circuits Central Can Help You Design and Manufacture Quality Printed Circuit Boards

No matter what kind of PCBs you require or how complex their application may be, Circuits Central can provide reliable PCB manufacturing, resulting in top-quality PCBs that will meet your needs. 

We function like a one-stop shop, as our talented and experienced experts in PCB and electronics manufacturing can handle every step of the process, from the schematic and PCB layout design to prototyping and quick-turn assembly to printed circuit board assembly (PCBA).

We even offer post-manufacturing testing and development services and post-production product upgrades to ensure that your product is up to the standards it must meet.

Whether you require assistance with just one of these stages in your PCB development and manufacturing process or with all of them, we are confident that you can benefit from our state-of-the-art and flexible-by-design production facility and our unmatched expertise in all things related to PCBs. 

Someone from our team would be happy to discuss your needs and help you determine how our full spectrum of services can help you achieve and exceed your desired outcomes. Not only will we provide everything you need to produce a top-quality PCB, but we will also do it in a highly economical and efficient manner and with incredible attention to even the finest details. 

For more information about our PCB manufacturing services or to learn more about some of the other PCB-related services that we offer, call Circuits Central at 1 (888) 602-7264 or contact us here.