The motherboard is the heart of the computer. It links all of the
components together into one machine. All computer components are connected to
the motherboard either through input/output ports, slots,
or adapter cards. There are built in components that can be removed that all
functioning motherboards contain. These components are the
central processing unit,
random access memory or RAM, the data BUS, and
adapter card slots. Another essential item is an
auxiliary storage device. These can
include hard disk drives, floppy disk drives, CD-ROMS, or other permanent
storage units.
A transistor is a type of electronic switch. It is made up of sections of n-typeand p-type semiconductors that switch a current on or off. An n-type semiconductor is a kind of semiconductor that has been treated to produce electrons. A p-type semiconductor is a kind of semiconductor that has been treated to produce holes (spaces for electrons). A controlling signal goes to the central section (the base or gate), which controls the flow of current through two outer sections (the emitter or source, and the collector or drain). If the signal is positive, the charge attracts negatively charged electrons out of the base. The rush of electrons out of the p-type silicon creates an electronic vacuum, and the electrons from the n-type source fill the vacuum up. Also, the electrons from the source flow to the drain, completing the circuit and making the transistor on, so that it represents a 1. If a negative charge is fed into the polysilicon, the electrons from the source are repelled, and the transistor is turned off.
A diode allows current to flow in one direction, but not the other. It consists of a p-n semiconductor junction. When a positive terminal is connected to the p-type layer (far right on the image below), the positive charge of the terminal attracts electrons and a full current flows. On reversing the connections (right), the negative charge of the p-type layer opposes electron flow. A low current flows as a few electrons freed by atomic vibrations cross the junction.
A capacitor is an electrical component that stores an electric charge.
