An electronic circuit, or part of a circuit, in which the conducting interconnection pattern is formed on a board. A thin board of insulating material is coated with a conducting film, usually copper. Photolithography is then used to coat part of the film with protective material. The unprotected metal is removed by etching, leaving the desired pattern of interconnections. Discrete components or packaged integrated circuits may then be added to complete the circuit.
Double-sided printed circuits are commonly produced in which both sides of the board have a circuit formed on them, with feedthroughs to connect the two sides as required. Printed circuits have been produced with several alternating layers of metal film and thin insulating film mounted on a single board. Boards with up to 12 layers of interconnections can be produced, commonly for digital systems.
The use of plug-in printed circuits in electric or electronic equipment facilitates maintenance and repair. Printed circuits are reasonably robust when subjected to careful handling.