Initially PCBs were designed manually by creating a photomask on a clear mylar sheet, usually at two or four times the true size. Starting from the schematic diagram the component pin pads were laid out on the mylar and then traces were routed to connect the pads. Rub-on dry transfers of common component footprints increased efficiency. Traces were made with self-adhesive tape. Pre-printed non-reproducing grids on the mylar assisted in layout. To fabricate the board, the finished photomask was photolithographically reproduced onto a photoresist coating on the blank copper-clad boards. COUNT 5
QSN1 In the old PCB design method, what was used to connect component pin pads? ANS1 traces QSN2 What did PCB designers used to employ on a mylar sheet? ANS2 photomask QSN3 What were traces originally made out of? ANS3 self-adhesive tape QSN4 Designers would rub on a dry transfer of what to make the process of laying out components simpler? ANS4 common component footprints QSN5 What kind of metal coated the blank boards used to make PCBs? ANS5 copper