Electronic devices are everywhere around us. Some of these gadgets are inconspicuous, while others draw much attention. But whether it’s a device that quietly monitors your health or a smartphone that bothers you with constant interruptions, they’ll all have a printed circuit board at their heart.
Printed circuit boards have been around since WWII when they were created for military use. Electronic manufacturers soon adopted this technology after it was introduced for commercial usage, as it provided a far more cost-effective alternative than traditional point-to-point electronics building.
Circuit board manufacturing has evolved to meet the growing needs for newer, faster, and more complex electronic circuitry. The details of how a PCB is made to perform what it needs to do may fill a library, but we’ll cover the basics of how printed circuit boards work I this article
What is a Printed Circuit Board?
A printed circuit board is a rigid framework that houses electrical circuitry composed of embedded metal wires known as traces and larger metal surfaces known as planes. Electronic components are soldered to metal pads on the upper, bottom, or both sides of the board. These pads link to the circuitry on the board, allowing the components to be connected. A single layer of circuitry, circuitry on the top and bottom, or numerous layers of circuitry stacked together can all be found on a circuit board.
To make the circuitry transmission as pure as possible, circuit boards are designed using a dielectric core material with low electrical conducting qualities and then interspaced with additional layers of metal and dielectric as needed. The common dielectric material for circuit boards is FR-4, a flame-resistant mixture of woven fiberglass fabric and epoxy resin. In contrast, the circuitry’s metal traces and planes are usually copper.
Printed circuit boards (PCBs) are used in various applications. Simple circuit boards are found in toys and controllers, whereas complex circuit boards are found in computers and telecommunications.
Some circuit boards are built of flexible materials, allowing them to be used in unusual cases and enclosures where they must bend around other device characteristics. Due to the high frequencies at which they operate, some boards are made with specialist materials. In contrast, others include thick layers of copper for high-powered circuits seen in industrial control panels and other related applications. Printed circuit boards are used in various applications, but they are normally designed similarly.
Printed Circuit Board Materials
Fiberglass or plastic substrates, copper, solder mask, and nomenclature ink are the most common materials used to make PCBs.
Fiberglass & Plastic Substrates
Depending on the intended PCB design, PCBs can be built on rigid or flexible base materials. Flexible circuits and stiff-flex flexible layers often use high-temperature polyimide films, whereas rigid PCBs typically use FR4 or polyimide fiberglass.
Polyimide (PI), liquid crystal polymer (LCP), polyester (PET), and polyethylene naphthalene (PEN) are all common plastic substrates for flexible circuits (PEN). The substrate aims to provide a non-conductive foundation on which the conductive circuits can be built and shielded from one another. In high-reliability or high-signal-speed applications, polyimide and LCP laminates are commonly utilized. Polyester and polyethylene naphthalene laminates are typically single layers of circuitry and are preferred for their low cost.
Copper
Copper is the most commonly utilized conducting material for circuitry in PCBs due to its high electrical conductivity. All laminates discussed above have thin copper foil sheets laminated to one or both plastic sides.
The fabricator then utilizes the designer’s Gerber files to image and etch the circuits to satisfy the customer’s specifications.
The PCB’s intended application determines the thickness and number of layers required. To build a multi-layered PCB, alternating copper circuitry and insulating materials are used.
Soldermask
Soldermask is a liquid applied to the outer layers of rigid PCBs and is commonly an epoxy substance. It’s also often employed on rigid-flex PCBs’ rigid parts. Soldermask is primarily used to protect copper circuits on outer layers from environmental oxidation. When the components are joined to the PCB, Soldermask is also designed to control and retain solder flow. Liquid solder could leak onto the PCB’s surface without a solder mask, connecting two nearby circuits and shorting out the board. Soldermask comes in various hues, including green, blue, black, red, amber, transparent, white, and many others.
Nomenclature
After the solder mask layers are done, the solder mask is printed with identifying information, marks, and sometimes barcodes. Nomenclature is the term for these marks, and it will be defined by files supplied with the other Gerber layers. They’re printed on the solder mask to assemble the PCB correctly.
Types of Printed Circuit Boards
Although all PCBs have the same basic purpose, they come in various designs and combinations to satisfy the needs of different applications. The following are some of the several varieties available on the market:
- Single-sided rigid
- Double-sided rigid
- Multi-layered rigid
- Single-layer flexible circuits
- Double-sided flexible circuits
- Multi-layered flexible circuits
- Rigid-flex
- High frequency
- Aluminum-backed
The following are the most prevalent types:
Rigid PCBs
Rigid PCBs account for the majority of the PCBs produced. These PCBs are utilized in applications where the PCB must be configured in a specific shape and remain that way for the duration of the device’s life. Rigid PCBs can range from a single-layer PCB to a multi-layer PCB with eight or ten layers.
Flexible PCBs
Flexible PCBs have good bending and folding characteristics, allowing them to fit into tight and irregularly shaped places. Because of this, they are highly adaptable and can be utilized to package tiny electronic equipment.
Rigid-Flex PCBs
Rigid-flex PCBs integrate the best features of rigid and flexible PCBs in one package. Unlike the other two types of circuit boards, these PCBs have all of the electronic interconnectivity concealed within the board, lowering the weight and overall size of the board. When ultra-light packaging is a must, they are a fantastic solution. They’re also more robust and dependable, with excellent strength and flexibility.
Multi-layer PCBs
Three or more double-layered PCBs are linked together to form multi-layer PCBs, with holes drilled in them to allow circuits to move from one to the next throughout the assembly. The most layers ever built were 50. Data storage devices, satellite systems, File servers, GPS technology, weather analysis, and medical equipment require multi-layer PCBs.
Double-layer PCBs
The copper and finish are present on both sides of the base material, distinguishing this PCB from single-layer PCBs. Circuits can pass from one side of the board through holes bored through the board.
HVAC systems, industrial controls, vehicle dashboards, power supply, vending machines, LED lighting, amplifiers, and instruments are just a few applications.
Single-layer PCBs
Single-sided PCBs, or circuit boards with only one layer of substrate or base material, are basic. A thin metal layer is applied to one side of the base material.
Copper is the most frequent coating due to its excellent electrical conductivity. A protective solder mask is put on the copper layer and a silkscreen coat on these PCBs.
Single-sided PCBs have the following advantages:
- Single-sided PCBs are used in mass manufacture and are inexpensive.
- Simple circuits like power sensors, relays, sensors, and electronic toys are made with these PCBs. Cameras, stereo equipment, calculators, radios, printers, power supplies, and solid-state drives, among other things, all employ them because of their low cost and significant volume.
High-Frequency PCBs
These are slightly different from standard PCBs regarding materials utilized and structure. They are capable of transmitting signals at a frequency of one GHz. Dielectric constant, dielectric thickness, and power dissipation are all factors to consider when selecting high-frequency PCBs.
These high-frequency items can be found in various applications, including advanced communications systems, industrial and medical uses. Cell phones, RF remote controls, GPS receivers, and ZigBee use high-speed products for better signal delivery. Airborne and ground-based radar systems are excellent examples of high-speed circuits.
Surface Mount Vs. Through Hole PCBs: What’s the Difference?
The type and style of components to be utilized is one of the first considerations made during the layout of a printed circuit board (PCB). The PCB’s electrical needs mostly influence this option. Still, if those are met, common component types such as resistors, capacitors, and diodes can typically be selected from a range of accessible combinations and footprints. The size and look of the finished printed circuit board assembly will be influenced by the component types chosen (PCBA).
The following is a quick comparison of the through-hole and SMT methods for PCB designers to utilize as a decision-making tool.
Through-Hole Technology
Despite the fact that through-hole components are the elder of the two technologies, there are still good reasons to use them. Because the holes that take the component leads are placed widely apart than the surface pads on an SMT type, any hobbyist with a soldering iron can create a through-hole PCB or a small batch of them with minimal fuss.
The typical hole center to hole center spacing is 0.100″ or larger for DIP processors. Through-hole PCBs are simple to hand-solder because of the broad spacing. There’s no chance of mistakenly forming bridges between pins on a single component or between adjacent components. Once the board is fully constructed and powered up, this reduces troubleshooting and rework.
Through-hole boards are also useful in more professional environments, especially during prototyping. Through-hole components can be included in the prototype layout to allow for speedy assembly of the board for basic proof-of-concept testing.
After the board has been successfully tested and proven to function, the designer can replace the larger SMT types with smaller SMT types with the same values and adjust the PCB layout to fit inside a smaller footprint for final testing and production.
Doing things this way could save project money upfront, especially if a small batch is subcontracted to an outside assembler. Keep in mind that outside service providers often charge a premium for small batches, as they want to put up large volume production runs that keep their machines running.
Surface Mount Technology
Regardless of the arguments for employing through-hole components on your PCB, surface-mounted components have several advantages that through-hole components cannot match.
One of the most obvious benefits is that significantly higher component density and processing power can be achieved while fitting everything into a much smaller and lighter overall PCBA. The efficient utilization of available surface area becomes increasingly important as the devices controlled by PCBs become smaller and smaller. SMT technology has become a must.
What Do Printed Circuit Boards Do?
PCBs allow electrical or data circuits to be assembled into a working piece of hardware. Conductive pathways, which are tracks or signal traces etched into the board’s metal surface, offer mechanical support and electrical connections. Without them, a large range of electronic devices would not be conceivable.
The following are some examples of common PCB applications:
- Printers and Computers
- Stereos and Televisions
- Amplifiers, Musical instruments, and synthesizers
- Digital clocks and signage
- Appliances
- Mobile devices
In reality, the number of possible applications is practically limitless. PCBs are used in practically every industry to support various goods and technologies.
What Is the Difference Between PCBA and PCB?
Printed circuit board (PCB) and printed circuit board assembly (PCBA) are essential terminologies in the electronics industry. Some people confuse the two, but they are two different things.
The fundamental distinction between these two names is that a PCB refers to a blank circuitry board, while a PCBA refers to a board that includes all electronic components required to function correctly. A PCB is not yet functional because it lacks the necessary components, but a PCBA is entirely functional. A PCBA is created on top of an existing PCB. PCBs and PCBAs are two different parts of the same process.
Advantages of PCBs
PCBs, provide myriad advantages over traditional circuit boards, making them the go-to solution for most electronics manufacturers. PCBs provide the following benefits:
- Eliminate cumbersome wiring and components, as well as their connections, to save space and time.
- Maintain your position regardless of the board’s movement.
- Connecting through copper tracks rather than linked components eliminates loose connections and short circuits.
- Reduce electronic noise by adopting shorter paths, which results in less radiation and electromagnetic wave pickup.
- Because of their increased scalability can be used in a wide range of applications, including large production runs.
- Because they are easily and efficiently mass-manufactured, they can be produced more quickly and at a lesser cost.
Facts about PCBs
Printed circuit boards are ubiquitous in today’s world. They’re in smartphones, tablets, computers, radios, and other electronic devices. Even though they surround us, some of us may have little knowledge of PCBs. Here are some facts about PCBs to help you learn more about them.
Who invented PCBs?
Although the work leading up to the conception of the circuit board may be traced back to the 1890s, Paul Eisler, an Austrian inventor, is credited with the invention of the printed circuit board. The printed circuit board was invented by Paul Eisler in 1936 while working on a radio set, although it was not widely used until after the 1950s. From that point on, the popularity of PCBs began to skyrocket.
Why are PCBs green?
You’ve probably noticed that most printed circuit boards are green, and you’re probably wondering why. The green color on the circuit board is the color of the solder mask, which is visible through the glass epoxy. The solder mask’s job is to keep moisture and dust out of the electronic lines’ underneath. In reality, the solder mask can be any color, including orange, blue, and yellow, rather than merely green.
- The majority of circuit boards are green for several reasons:
- The color green is thought to have been chosen as a regulating standard for PCBs when the American military first utilized them, and it has since spread throughout the world.
- The glass epoxy’s original color is a natural green, and it can still be utilized to keep things traditional.
Finally, the green color is often utilized in PCB production because it makes it easier for engineers to spot defects in the trace lines.
Circuit boards are miniaturizing
As technology advances and devices become smaller, we can see this reflected in the PCB industry. Smaller PCBs are being developed faster than ever before to address the demand for smaller and more compact circuits.
There has also been an investigation into the possible applications of graphene for PCBs, as they are good electrical conductors. Because graphene does not require the same cooling methods as present circuits, it may help miniaturize PCBs even further.
There are a variety of PCB types
Printed circuit boards (PCBs) aren’t all created equal. In reality, there are various circuit boards, each with its own set of properties that make it suitable for specific applications. Some boards are better suited to low-performance devices, which implies they are less expensive and easier to produce.
On the other hand, other boards may be better suited to high-power devices but are more expensive to manufacture. The following are various boards: Flexible, rigid, flexible-rigid, and metal-backed.
You can customize Printed Circuit Boards.
Did you know that Printed Circuit Boards (PCBs) can be tailored to your precise requirements? You can ask a PCB business to design and produce circuit boards that meet your exact specifications. A custom PCB may be preferable to a regular PCB if you add more functionality to a device.
PCBs utilize traces, not wires.
Electric gadgets that require wires to transport energy may be known to you; nevertheless, PCBs are exceptions. These circuit boards transfer electrons via copper traces rather than wires. These traces are much thinner and flatter than standard wires, which takes up less room. Copper traces prove more efficient than wires when connecting small components on a circuit board.
They have lots of components.
Circuit boards are made up of various components since they are complicated electronics. Each of these components has a unique set of features and functions on the circuit board. Capacitors, resistors, inductors, diodes, batteries, fuses, transistors, and more are just a few of the components you may expect to find on a PCB.
There are two main manufacturing techniques.
There are two major methods of putting components onto a circuit board for manufacturing and mounting processes. Surface mount technology and through-hole technology are both available.
THT, or through-hole mounting, was invented in the 1940s and has become a widespread component mounting method. Through-hole uses holes that are bored into the PCB. The leads of the components are then fed through and soldered to the pads.
Surface mount technology, which allows components to be mounted directly on the board’s surface, was invented in the 1960s. This eliminated the need for drilling holes in the PCB, allowing for automated component mounting and soldering, saving time and money while ensuring a more consistent circuit.
PCBs are used everywhere.
PCBs are used in practically every electrical application, as you may or may not be aware. Printed circuit boards are utilized in various electronic devices, from simple to complex smartphones, tablets, and computers. Even though we utilize electronic devices daily, we often overlook the significance of these circuit boards in modern technology.
They are created using computer-aided design (CAD)
Computer-Aided Create, or CAD for short, is used to design printed circuit boards, which are highly sophisticated bits of electronics. Technicians use CAD to create many components of the PCB, such as the schematic and layout. Essentially, by utilizing CAD software to create a PCB, you can test the board to verify if all of the traces are properly linked before putting it together physically.
Conclusions
Professionals in various industries use printed circuit boards to improve the performance and production of their electronic systems. It is feasible to construct packaging for your electrical equipment optimized for its end application by carefully selecting materials and PCB fabricators.
We hope that this thorough overview of printed circuit boards (PCB) has provided you with a better knowledge of what they are, how they work, what they are composed of, and most importantly, what they do. Lastly, if you are looking to purchase or order for Printed Circuit Board (PCB), contact us at ICRFQ to day for quality and fast delivery turn arounds.
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