There is usually a thin layer of conductive material, like copper, on one side, then a solder mask, and finally a silkscreened ‘roadmap’ of the different elements to be soldered on.

Many PCBs are rigid, think of a computer motherboard that is a solid board that slots into the computer housing, however, flexible PCBs also exist that are usually made from flexible, light, and environmentally resistant plastics and can flex around corners or into awkward shapes. This saves space and weight and makes them useful in applications where multiple rigid PCBs would be too cumbersome (such as aerospace) or could be affected by vibrations or extreme temperatures, for example.

The different types of PCB are used in different applications:

• Single-layer PCB – the easiest to design and manufacture. These simple PCBs are inexpensive and often used in high-volume electronics like calculators, weighing scales, power supplies, and other common consumer electronics that are made at a serious scale.

• Double-layer PCB – has circuits and components on both sides of a board saving space and allowing more complex functions to be performed. As such, these are used in more complicated electronics such as automobiles and industrial machinery controls.

• Multi-layer PCB – each PCB has several layers, usually between 4 to 12. The boards are glued together with insulating layers between them. Due to the increased capacity for circuits and components, all of whom can connect through the layers, these are used in complex electronics such as satellites and servers.