The Anatomy of a Printed Circuit Board What Are PCBs and How are They Used?

Prototype pcb fabrication

Every piece of modern technology that we possess would not be possible if it were not for circuit boards. Fundamentally, a circuit board allows an electric current to travel on a set path to different components. Although it may seem like a basic process, circuit boards allow for a wide array of complex procedures that power everything from alarm clocks to computers and everything in between.


What are Printed Circuit Boards?

Prior to the introduction of integrated printed circuit boards, connections were made on a point-to-point wiring system; this kind of system lead to frequent failures at the wire junctions and short circuiting where wire insulation began to age and crack. Prototype circuit boards have been around since the early 1900s and gradually became refined over the years to represent the modern printed circuit boards of today. Prototype PCB manufacturing is used in an endless number of industries and had a net worth of nearly $60 billion as of 2012 — today’s figures are even higher as advancements in the field are opening up a growing number of possibilities and applications for prototype PCB manufacturing.


The Anatomy of a Prototype Printed Circuit Board

Every printed circuit board is uniquely designed for its own function with designers using computers to set the layout, size, and spaces between electrical paths for each board. Every board starts with a base material or substrate, FR-4 glass epoxy is the most frequently used base material today. On top of the substrate is a thin layer of copper foil that acts as the conductor to carry the signal to the components. On top of that copper layer is a green soldermask layer that helps to insulate the copper and prevent accidental contact between components which are either connected through the older “through hold technology” or the newer “surface mount technology.” The earliest printed circuit boards could only offer single-sided construction, but today’s printed circuit boards also offer a double-sided and multi-layered construction for more advanced circuits.


Prototype PCB Manufacturing and Assembly

Components are attached to printed circuit boards using eutectic solder which is composed of 63% tin and 37% lead — this solder simultaneously melts and solidifies at 183 degrees Centigrade without going through a flowing, partially solid phase typical of most solders. The components are affixed to the printed circuit board with the help of a legend that indicates component designators, switch settings, test points, and other assembly indications; these legends are printed using silk screen printing, liquid photo imaging, or ink jet printing. Many prototype PCB manufacturers utilize advanced surface mount technology (SMT) placement machines and bulk wave soldering to increase production although several facilities continue to utilize skilled technicians that are able to solder parts as small as 0.02 inches by 0.01 inches. As new breakthroughs in technology continue to develop, printed circuit boards will continue to evolve to continually push the limit on what can be achieved.

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