Printed circuit board
Laminated board connecting electronic components via etched copper traces.
A printed circuit board (PCB), also known as a printed wiring board (PWB), is a laminated sandwich structure of conductive and insulating layers, each with a pattern of traces, planes and other features etched from one or more sheet layers of copper laminated onto or between sheet layers of a non-conductive substrate. PCBs are used to connect or wire components to one another in an electronic circuit, with electrical components fixed to conductive pads on the outer layers, generally by soldering. They are used in nearly all electronic products today, replacing earlier methods such as wire wrap and point-to-point construction.
- field
- Electronics manufacturing
- known_for
- Laminated sandwich structure of conductive and insulating layers for connecting electronic components
- market_value_2014
- US$60.2 billion
- market_value_2024
- US$80.33 billion
- market_value_2029_forecast
- US$96.57 billion
Lore & Background
The development of methods used in modern printed circuit boards started early in the 20th century. The Centralab Division of Globe Union submitted a proposal using thick-film technology, screenprinting metallic paint for conductors and carbon material for resistors on a ceramic plate, with ceramic disc capacitors and subminiature vacuum tubes soldered in place. The resulting patent was classified by the U.S. Army and assigned to Globe Union. Printed circuits did not become commonplace in consumer electronics until the mid-1950s, after the Auto-Sembly process was developed by the United States Army.
Reader's Guide
Printed circuit boards are fundamental to modern electronics, enabling mass production of circuits cheaper and faster than earlier wiring methods such as point-to-point construction or wire wrap. They require additional design effort to lay out the circuit, but manufacturing and assembly can be automated, and electronic design automation software is available to do much of the layout work. PCBs can be single-sided, double-sided, or multi-layer, with multi-layer boards providing much higher component density. The rise in popularity of multilayer PCBs with more than two, and especially more than four, copper planes was concurrent with the adoption of surface-mount technology. However, multilayer PCBs make repair, analysis, and field modification of circuits much more difficult and usually impractical. Since the 1980s, surface mount parts have increasingly replaced through-hole components, enabling smaller boards and lower production costs, but making repairs more challenging. Recent advances include 3D printed electronics and HDI technology, which allows for denser designs with blind/buried vias and microvias.
Did You Know?
- The world market for bare PCBs exceeded US$60.2 billion in 2014.
Frequently Asked Questions
What is a printed circuit board (PCB)?
A PCB is a flat, laminated sandwich of copper conductive traces bonded to non-conductive material, designed to route electrical signals between parts. Components are typically soldered onto exposed copper pads on the board's outer surfaces.
How does a PCB connect electronic components together?
Instead of discrete wires, a PCB uses etched copper pathways—called traces—embedded within insulating layers to carry current between parts. Components are fixed to designated pads, generally by soldering, creating a compact and reliable circuit layout.
Why are printed circuit boards so important in modern electronics?
PCBs serve as the structural and electrical backbone of nearly every electronic product made today. They replaced bulkier, less reliable assembly methods like wire wrapping, enabling dense, repeatable, and mass-producible circuit designs.
What did printed circuit boards replace in earlier electronics?
Before PCBs became standard, circuits were often assembled by hand-tying individual wires to component pins, a technique known as wire wrapping. PCBs made assembly far faster, more compact, and dramatically more reliable for large-scale production.
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