What is PCB

From design week we switch to the electronics production.So all work of electronics based on circuit and which is make on the pcb board.Thats why we first know about what is pcb.
PCB-printed circuit board
(according with wiki)
A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components (e.g. capacitors, resistors or active devices) are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate.



Source:internet

I got confused beacuse on the internet we find that the most common pcb substate is fr 4 and I go thought all pcb have same material on further research I found that fr 1 is different and doesnt have glass fiber in it .

(according with wiki)FR-1 is a hard, flat material that consists of a thin layer of copper over a non-conductive phenolic resin. Itís usually about the thickness of two or three credit cards. and not glass epoxy substrate.

I am using the FR-1 material for making circuit