Materials in Circuits
- After studying this section, you should be able to:
- • Identify electrical conductors on a PCB.
- • Identify common insulating and conducting materials and their uses on a PCB.
Conductors and Insulators in circuit boards.
A good example of how various materials are used for conductors and insulators in electronics can be seen on the printed circuit board shown in Fig. 1.2.1.
Fig. 1.2.1 Micro-controller Circuit Board
- The conducting strips are made from copper, which is a very good conductor.
- Electrical connections between the components and copper strips are made with solder (mainly tin), which is another good conductor, and has the advantages of being easy to melt, as well as making good electrical and mechanical contact.
- The board itself is made from a good insulator, usually paper impregnated with resin, which is known as SRBP (synthetic resin bonded paper), or in high quality boards from glass-fibre board. Glass, paper and resin are all very good insulators.
- The contacts of the chip holder are gold plated. This gives an excellent low resistance contact and also prevents tarnishing (oxidisation), which would otherwise increase the contact resistance over time.
- The chip is encapsulated in black resin; this gives good electrical insulation and, being black, provides good heat conduction to disperse heat generated within the chip.