History in the Advancement of the Printed Circuit Board
In the 1850s, the development of electronic connection systems prepared the ground for the evolution that leads to the creation of printed circuit boards. Electric elements that were big and cumbersome were attached to each other by means of strips of metal, which were afterwards replaced by wires hooked up to screw terminals. The substrates on which these components were placed were originally made of wood, and were later replaced by metal chassis.
The resulting increase in component density and closely spaced electric trails started a new time in PCB design. Components on a printed circuit board are electrically attached to the circuits by two different strategies : the older'through hole technology' and the newer'surface mount technology.' With through hole technology, each element has thin wires, or leads, which are pushed through little holes in the substrate and soldered to connection pads in the circuits on the opposite side. Gravity and friction between the leads and the sides of the holes keeps the parts in place till they are soldered. With surface mount technology, stubby J-shaped or L-shaped legs on each component contact the printed circuits immediately. Though surface mount technology needs greater care in the placement of the elements, it eliminates the time-consuming drilling process and the space-consuming connection pads inherent with through hole technology. Both technologies are used today.
Two other types of circuit assemblies are related to the printed circuit board.
The miniaturization of electrical items continues to drive printed circuit board producing towards smaller and more densely packed boards with increased electronic capabilities. These and other advancements will keep the construction of printed circuit boards a dynamic field for several years.About the Author:
The author is a freelance writer on technological reviews and frequently writes about manufacturing subjects in matters pertaining to PCBs.