Most people associate a printed circuit board (PCB) with computers and other high-tech equipment. But their history goes back nearly a century, to 1936 when an Austrian inventor named Paul Eisler developed the first PCB.
That original board would be virtually unrecognizable compared to modern PCBs but the underlying technology is still there.
What is a printed circuit board? Let’s look at what they are and how they’re used in today’s world.
What Is a Printed Circuit Board and What Does It Do?
A printed circuit board, also known as a PCB, makes it easier for manufacturers to assemble electronics and other electrical devices. The PCB is a board that has a lot of the wiring and other connections “printed” on the surface.
Components like microprocessors, capacitors, resistors, and other electronics parts attach to the PCB. The printed connections are already in place so the components don’t need to be wired together in each device.
When manufacturers design a new device, they might create the circuits manually or use a breadboard system to work out the details. But once they have a functional product, a PCB printer can mass-produce the circuit boards based on that design.
Advantages of PCB Over Traditional Circuit Boards
Printed circuit boards have quite a few advantages over traditional circuit boards. Some of the more valuable benefits include:
- More compact so devices can be smaller
- Avoid loose connections and short circuits
- Can be manufactured quicker and in larger quantities
- Shorter electrical pathways reduce the chance of electronic noise and interference
Once the manufacturer settles on an efficient design, PCBs can be made for a lower cost than other types of circuit boards as well. This will make a huge difference in profitability for products like Apple’s iPhone and iPad that sell millions of units every quarter.
Types of PCBs
PCBs have several different designs, each of which has particular applications.
Single-layer PCBs have the circuitry on one side only. These are the most simple designs and get used in less complex devices like calculators, digital cameras, radios, and power supplies
Double-layer PCBs are similar to single-layer but have circuitry on both sides of the board. This supports a more complex design in virtually the same amount of space. These boards have holes drilled in them to allow connections from one side to the other.
Double-layer boards are often used in HVAC systems, car dashboards, amplifiers, and industrial control systems.
Multi-layer PCBs have more than one board attached together, again with holes drilled to allow connections between layers. These boards allow more complex designs to fit into nearly the same physical space as single- and double-layer designs.
Multi-layer designs could have as few as 3 PCBs or as many as 50. Computer servers, network storage devices, satellites, and medical equipment typically use multi-layer printed circuit board designs.
Flexible PCBs are printed on materials that let the board twist and bend. The fundamental design is the same but these flexible materials allow the use of the boards in devices that need to allow that sort of movement. These boards come in single, double, and multi-layer designs.
As you can probably guess, rigid PCBs use rigid materials for the board. These are the most common type and get used in devices that don’t need to bend or twist. Once again, they’re available in all three-layer designs.
Rigid-flex PCBs use a combination of the two. This allows them to work with a wide range of product designs, particularly where space is at a premium. The flexible portion of the board can accommodate bend or moving parts, allowing the board to fill more available space.
How Are Printed Circuit Boards Designed?
CAD software (computer-aided design) is typically used to design printed circuit board layouts. This software lets designers go through various “what-if” scenarios when working out the layout for aboard.
Some of the important factors to consider when designing a PCB include:
- Amount of space you have to work with
- The environment the device will be used in
- Installation and manufacturing limitations
- Rigid or flexible PCB
These all have to get factored into the design so the PCB designer usually has to work with product design, engineering, manufacturing, and various other divisions to ensure they meet all of their needs.
Common Applications for PCBs
PCBs are used in a lot of the products you use every day. Computers, smartphones, kitchen appliances, and many other common household items are designed using a PCB. They’ve had a significant impact in a few markets, however.
Modern imaging systems, MRI machines, X-ray machines, and medical computers all benefit from the use of PCBs. They allow these devices to get thinner and smaller, which means they can fit into smaller spaces in hospitals and other facilities. It also means devices like hearing aids and pacemakers continue to get smaller and less intrusive.
Aerospace and Military Applications
PCBs get used in instrument panels, flight control systems, safety systems, and other important components of planes and other aircraft. Rigid-flex designs let these PCBs work in high-vibration environments, which makes them more reliable than traditional circuit designs.
Consumer and Commercial Electronics
Consumer and commercial electronics applications are where most people see the biggest benefits from PCBs. This is one of the key components that make the smartphone that you carry in your pocket more powerful than a computer that would have taken up an entire room 20 or 30 years ago.
PCB Design is Constantly Evolving
Hopefully, that answers the question, “What is a printed circuit board?” for you. While you don’t need to know how they work to use modern technology, knowing a bit more about them can help you understand more about those high-tech tools in your life.
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