PCBs form the basis of virtually all electronic circuits today, technology in this area of electronics is moving forward. Printed circuit boards can be made from a variety of substances. The most widely used in a form of glass fiber based board known as FR4. but the original PCB is from paper phenolic aldehyde.
The products of single-sided boards came out centered in American with the appearance of transistor in early 1950s. At that time, it mainly produced by etching the copper foil directly.
During 1953~1955, Japanese utilized imported copper and produced paper phenolic aldehyde copper foil substrate for the first time and widely used in radio products. In 1956, after the appearance of Japanese professional manufacturers, the manufacturing technology for single-sided board improved rapidly. For materials, in early stage mainly was paper phenolic aldehyde copper foil substrate; but as phenolic aldehyde materials has weak electric insulativity, weak soldering heat-resistance, distortion and other disadvantages, gradually appeared paper epoxy resin, glass fiber epoxy resin.
Currently the single-sided boards that used in consumer electronics are mainly fiber glass FR4 substrates. Single-sided boards concentrate the parts on one side and wires on the other side. As the wires only appear on one side, thus we call this board single-sided board. There are strict limits on single-sided board, as it has wires on one side and the wires cannot cross and must have their own ways, only early circuits used this kind of boards.
