Program Proiectare

SCAD is software for creating solid 3D CAD program Proiectare. UNIX, MS Windows and Mac OS X.

Jump to navigation Jump to search Not to be confused with Printed electronics. For the defunct company, see Printed Circuit Corporation. This article needs additional citations for verification. Printed circuit boards are used in all but the simplest electronic products. They are also used in some electrical products, such as passive switch boxes. Alternatives to PCBs include wire wrap and point-to-point construction, both once popular but now rarely used. PCBs require additional design effort to lay out the circuit, but manufacturing and assembly can be automated.

Specialized CAD software is available to do much of the work of layout. Multi-layer PCBs allow for much higher component density, because circuit traces on the inner layers would otherwise take up surface space between components. Before the development of printed circuit boards electrical and electronic circuits were wired point-to-point on a chassis. Typically, the chassis was a sheet metal frame or pan, sometimes with a wooden bottom. Development of the methods used in modern printed circuit boards started early in the 20th century. In 1903, a German inventor, Albert Hanson, described flat foil conductors laminated to an insulating board, in multiple layers. Thomas Edison experimented with chemical methods of plating conductors onto linen paper in 1904.

The Austrian engineer Paul Eisler invented the printed circuit as part of a radio set while working in the UK around 1936. In 1941 a multi-layer printed circuit was used in German magnetic influence naval mines. Printed circuit boards were introduced to reduce the size, weight, and cost of parts of the circuitry. In 1960, a small consumer radio receiver might be built with all its circuitry on one circuit board, but a TV set would probably contain one or more circuit boards. The ECME could produce three radio boards per minute. During World War II, the development of the anti-aircraft proximity fuse required an electronic circuit that could withstand being fired from a gun, and could be produced in quantity.

The board is double sided, with through-hole plating, green solder resist and a white legend. Both surface mount and through-hole components have been used. Originally, every electronic component had wire leads, and a PCB had holes drilled for each wire of each component. The component leads were then inserted through the holes and soldered to the copper PCB traces. This method of assembly is called through-hole construction. In 1949, Moe Abramson and Stanislaus F.