What is PCB?Posted by Indiacircuit on December 10th, 2018 The full form of PCB is Printed Circuit Board. The history of the PCB took us to early 20th century. The PCB we know today is first in use after 1943. In 1925 an American named Charles Ducas apply for patent for creating an electrical path on insulted surface with the help of stencil with electrically conductive ink. After this it is known as printed wire or printed circuit. The first working printing wiring board made by an Australian scientist Dr. Paul Eisler in 1943. In early 1920s the PCB made with materials like Bakelite, Masonite and layered cardboard and with wooden planks. The holed were drilled and flat brass wires were riveted or bolted with nut and bolt. The components are pressed at brass traced onto a hollow rivet and components lead pressed into open end of rivet. Sometimes nuts and bolts were used instead of rivets. In 1950 and early 1960s there are different materials used like mixed with different resins. But the PCBi s still single sided. The circuitry is on the one side and components on the other side. The PCB changes the different products with its c small size and make product better. For the fast development of PCB, thanks to different government agencies who want to made communication equipments and weapons more powerful. The processes were developed theta copper plate onto the drilled holes. This allows circuits connected both sides electrically. The brass is replaced with copper due to its conductivity, low cost and easy manufactured. The process is to make PCB is patented in 1956 by scientist of American Army. The base material is used is melamine which have layer of copper foil. A drawing of wiring pattern and photographed on zinc plate and this plate is used for an offset printing. An acid resistant ink printed onto copper foil and etched to remove the exposed copper. Other methods like stencils, screening, hand printing and rubber stamping were used. Holes were punched in patterns to match the position of the components. The laminated material and card was dipped in a molten solder. The solder coat the traces and connecting the components with the traces. The complexities and densities increasing draw the development of layers of copper traces between layers of dielectric material. In 1961 multilayer PCB were used first. The development of transistor and minimize other components draw more manufacturers in PCB manufacturing for wide range of products. The multi layer PCB save space in product which helpful in space equipment, telecommunication equipment and defense systems where they have minimal space to use for maximum output. The inventions of integrated circuit these minimize the circuit size. The improving technology of PCB made large market for PCB manufacturer. When we see the PCB why the solder mask of PCB is green? It has various reasons. The first one is how the colour is affected the eyes of the worker during assembling the PCB by hand. The brownish yellow colour is used and mixed with resin and the output is honey brown colour which is not appealing to eyes. After using various mixtures they finally succeed in making of hue green colour which is mixing of yellow and blue. The green colour is accepted by all the pcb manufacturer and it is standard for all PCB and still uses today. Source-http://indiacircuit.com Like it? Share it! |