Conductors, Insulators, and Semiconductors
The DC electrical flow inside the computer, or outside for that matter, travels over a
conductor,which is any material, such as copper or gold, that readily carries electricity
withoutmuch resistance. It is common that a conductor is wrapped or coated by another
material, called aninsulator,such as rubber, that is not a good conductor of electricity. A
good and easily found example is the cord to your lamp. Most likely it is a rubber cord
with copper wires inside. The copper wire is the conductor and the rubber coating is the
insulator.
Many of the electronic components inside the computer are neither conductors or in-
sulators. They are made of materials, such as silicone, that is both and neither a conductor
or an insulator. These materials, which can be made chemically and electronically to be
either conductive or insulating, are calledsemiconductors. Depending on the type and
purpose of a circuit, a semiconductor can be set to provide the right action. A semicon-
ductor could also be called a semi-insulator, but so far this name hasn’t caught on.The Electronic Building Blocks of the PC
Four primary electronic components are used on virtually every electronic circuit inside
the computer. Each of these components provides a specifically different function to each
circuit. These components are resistors, capacitors, diodes, and transistors. Aresistorslows down the flow of electrical current in a circuit.
Acapacitoris used to store electrical charges. Most of the computer’s capacitors
are small, but there are some large capacitors in the computer that hold enough
charge to kill you, such as those in the monitor and power supply.
Adiodeforces the electricity to flow in one way only.
Atransistor,which was mentioned earlier in the chapter, stores a single binary
digit (bit).Another basic electronic component found in the circuitry of the PC is the logic gate.
Alogic gateis created from a combination of resistors, capacitors, diodes, and transistors.
Circuits are made up of logic gates and electronic systems are made up of circuits.
Perhaps the most important electronic component in the computer is the microprocessor.
The microprocessor controls the function of virtually all other electronic components of the
computer. Chapter 3 covers the various processors, past and present, used in PCs.(^36) PC Hardware: A Beginner’s Guide