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Printed circuit board

technology Maturity 9-11 Next article →

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

SEG DVD 430 - Printed circuit board-4276
SEG DVD 430 - Printed circuit board-4276

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.

Hand Etched PCB
Hand Etched PCB

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

Mouse printed circuit board both sides IMG 0959a
Mouse printed circuit board both sides IMG 0959a

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.

Hand Etched PCB
Hand Etched PCB

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.

MK53 fuze
MK53 fuze

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.

MK53 fuze
MK53 fuze

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.

Surface Mount Components
Surface Mount Components

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.

PCB Spectrum
PCB Spectrum

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.

Surface Mount Components
Surface Mount Components

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.

Breakout board
Breakout board

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

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🖼️ Images & Media (13)
File:SEG DVD 430 - Printed circuit board-4276.jpg
SEG DVD 430 - Printed circuit board-4276.jpg
File:PCB Spectrum.jpg
PCB Spectrum.jpg
File:Mark-53-proximity-fuze-1943.jpg
Mark-53-proximity-fuze-1943.jpg
File:Hand Etched PCB.png
Hand Etched PCB.png
File:Resistors (1).jpg
Resistors (1).jpg
File:MOS6581 chtaube061229.jpg
MOS6581 chtaube061229.jpg
File:Box of 02in pcb bits.jpg
Box of 02in pcb bits.jpg
File:Surface Mount Components.jpg
Surface Mount Components.jpg
File:Mouse printed circuit board both sides IMG 0959a.JPG
Mouse printed circuit board both sides...
File:Breakout board.jpg
Breakout board.jpg
File:SD Card Breakout Board.jpg
SD Card Breakout Board.jpg
File:Cordwoodcircuit.agr.jpg
Cordwoodcircuit.agr.jpg

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