CHAPTER 20. ELECTRONIC PROPERTIES OF MATTER 20.4
Integrated circuits are miniaturised circuits. Theuse of integrated circuitsmakes it possible for
electronic devices (like acellular telephone or a hi-fi) to get smaller.
Microprocessors are a special type of integrated circuit.Activity: Semiconductors
Assess the impact on society of the invention oftransistors, with particular reference to
their use in microchips (integrated circuits) and microprocessors.Chapter 20 — Summary
See the summary presentation ( Presentation: VPrpp at http://www.everythingscience.co.za)- There are two types ofconductors, metals andsemi-conductors.
- Overlapping electron orbitals in a crystal latticeform a ”band”.
- The gap between valence and conduction bands determines whether amaterial is a good
conductor, semi-conductor or insulator. - Doping is the deliberate addition of impuritiesto a substance to alter the electrical properties.
- Adding a dopant that has more valence electrons is n-type doping (a donor impurity).
- Adding a dopant that has less valence electronsis p-type doping (an acceptor impurity).
- Combining p- and n-type semi-conductors creates a junction through which current flows more
easily in one direction than the other.
Chapter 20 End of Chapter Exercises
- Compare p- and n-type semi-conductors.
- Explain how a p-n junction works using a diagram.
- Give everyday examples of the application.
- What is a conductor?
- What is an insulator?
- What is a semiconductor?
More practice video solutions or help at
http://www.everythingscience.co.za(1.) 00wc (2.) 00wd (3.) 00we (4.) 01xv (5.) 01xw (6.) 01xx