Refining of precious metals

Printed circuit boards. A little history

Printed circuit boards originated from electrical connection systems developed in the 1850s. Metal strips or rods were originally used to connect large electrical components mounted on wooden bases. Over time, the metal strips were replaced with wires connected to the screw terminals, and the wooden bases with metal ones. However, over time, smaller and more compact designs were needed due to the increased operational needs of products using panels. 1925 Charles Ducas of the United States filed a patent application for a method of creating an electrical path directly on an insulated surface by printing through a stencil with electrically conductive wires. This method gave birth to the name “printed installation” or “printed circuit board”.

1943 Paul Eisler of the United Kingdom patented a conductive pattern or method of etching chains on a layer of copper foil bonded to a glass-reinforced, non-conductive substrate. The Eisler technique was not widely used until the 1950s, when the transistor was introduced for commercial use. Until then, the size of vacuum tubes and other components was so large that only traditional fastening and wiring methods were required. However, with the advent of transistors, components have become very small, and manufacturers have turned their attention to printed circuit boards to reduce the overall size of electronic packaging.

New technologies and their use in multilayer printed circuit boards in 1961. patented by the US company Hazeltyne. As a result, the increased density of components and closely spaced electrical paths ushered in a new era in the design of printed circuit boards. Integrated circuit chips were introduced in the 1970s, and these components were quickly incorporated into printed circuit board design and manufacturing techniques.