Printed circuit board

Small boards help things work.

These boards use thin metal paths. These paths act like tiny wires. They connect parts together.

This helps power move around. The paths are etched onto the board. This makes them stay in place. Some boards have many layers. This lets them hold more parts. They make electronics small and light.

Most things use them today. It is like a tiny map!

A printed circuit board, or PCB, is a special tool. It helps connect parts in electronic devices.

A PCB is like a sandwich. It has layers of insulating material. Between these layers, there are thin paths of copper. These copper paths are called traces. They act like flat wires to move power.

To make these traces, builders use a way called etching. They use a light-sensitive coating called photoresist. This coating protects the copper we want to keep. A liquid then washes away the rest.

Some boards have only one side of copper. Others are multi-layer. These have many layers stacked together. This lets the board hold many more parts. To connect different layers, builders use tiny metal-lined holes. We call these vias.

In the past, people used many loose wires. This was slow and made things heavy. Now, machines can build many PCBs at once. This makes them cheap and fast to make. Most electronics use them today.

A printed circuit board, or PCB, is a vital part of almost every electronic device today.

You can think of it as a laminated sandwich structure. It uses layers of insulating material to hold thin paths of copper. These copper paths are called traces, and they act like flat wires on a surface.

These traces connect different electronic parts to each other. By using a board, engineers can make devices much smaller and lighter.

Making a PCB involves a careful way it works called etching. First, a special coating called photoresist is put on the board. This coating is sensitive to light. When light shines through a pattern, it protects the copper that needs to stay.

Then, a liquid solution washes away the unprotected copper. This leaves behind the specific paths needed for the circuit. The board might also have a coating called solder mask. This mask protects the copper from rusting and prevents mistakes during assembly.

Long ago, electronics were built in a very different way.

Before PCBs, people used point-to-point construction. They attached parts to a heavy metal or wooden frame. They used many loose wires and solder to connect everything. This made devices very large, heavy, and fragile.

In 1903, Albert Hanson described using foil on insulating boards. Later, in 1936, Paul Eisler invented the printed circuit while working in the UK. By 1943, the United States used this technology for proximity fuzes in World War II.

There are many different ways to build these boards. Some are single-sided with one layer of copper. Others are multi-layer, meaning they have many layers stacked together.

These many layers allow more parts to fit in a small space. To connect the different layers, builders use tiny metal-lined holes called vias.

In the past, parts were attached using through-hole construction. This means the wire leads went through holes in the board. Now, many parts use surface-mount technology to save even more space.

Today, the world uses a huge number of these boards. In 2014, the market for bare PCBs was worth over $60.2 billion.

Experts think this will grow to $96.57 billion by the year 2029. You can find them in almost everything, from mobile phones to medical tools.

Even though they are small, they are the foundation of our modern world. They allow our technology to be fast, cheap, and very reliable.

A printed circuit board, or PCB, is a fundamental component in modern electronics.

It is a laminated sandwich structure made of conductive and insulating layers. These layers contain patterns of traces, which are conductive paths that act like flat wires on a surface. PCBs serve to connect or "wire" various electronic components to one another within a circuit. Without this technology, the compact and powerful devices we use every day would not be possible.

The manufacturing process of a PCB relies on a method called chemical etching. First, a pattern known as the "artwork" is prepared. A material called photoresist is coated onto the board. This resist is then exposed to light through the artwork pattern. The light-sensitive material protects specific areas of the copper from being dissolved. Next, the board is placed in an etching solution. This solution washes away the unprotected copper, leaving behind precise tracks, pads, and vias.

To prevent errors, a coating called solder mask is applied. This solder resist protects the copper from corrosion and prevents electrical shorts between traces.

There are several distinct types of PCB constructions based on their complexity. A single-sided PCB contains only one layer of copper. A double-sided PCB has two copper layers on both sides of a single substrate. Multi-layer PCBs consist of stacked substrate layers with copper plating sandwiched between them.

These multi-layer boards allow for much higher component density. This is because circuit traces can reside on inner layers rather than taking up surface space. To connect these different layers, manufacturers add vias. Vias are metal-lined drilled holes that enable electrical interconnections between conductive layers.

Before the PCB, engineers used point-to-point construction on a chassis. This chassis was often a heavy metal or wooden frame. Components were attached to the frame and connected using loose jumper wires or soldering. These older circuits were bulky, heavy, and quite fragile. The journey toward modern PCBs began in the early 20th century. In 1903, Albert Hanson described multi-layer foil conductors on insulating boards. In 1936, the Austrian engineer Paul Eisler invented the printed circuit while working in the UK.

By 1943, the United States used this technology on a large scale for proximity fuzes during World War II.

The transition to mass production involved many key developments. In 1948, the United States released the invention for commercial use. The Auto-Sembly process, developed by the US Army in 1949, allowed component leads to be dip soldered. This helped printed circuits become common in consumer electronics by the mid-1950s. Motorola was an early leader, investing $1 million to adopt "plated circuits" in home radios by 1952.

In the 1980s, surface-mount technology began replacing through-hole construction. This shift allowed for even smaller boards and lower production costs, though it made repairs more difficult.

The economic scale of this industry is massive. In 2014, the world market for bare PCBs exceeded US$60.2 billion. By 2024, the market was estimated at $80.33 billion. It is forecast to reach $96.57 billion by 2029, growing at 4.87% per year.

This growth is driven by the constant need for smaller and more efficient electronics. High-Density Interconnect (HDI) technology is a major part of this modern trend. HDI uses microvias to create much denser designs. A 4-layer HDI board can match the quality of an 8-layer through-hole board, which helps reduce costs.

Today, PCB technology connects to many advanced fields of science and engineering. HDI technology is essential for computer components, mobile phones, and medical equipment.

Recent advances in 3D printing have even introduced 3D printed electronics. This allows items to be printed layer by layer using liquid ink with electronic functions. Some modern PCBs even incorporate optical waveguides, which are similar to optical fibers. As technology advances, the printed circuit board remains the essential foundation for almost every electronic system in existence.