Zusammenfassung der Ressource
SEMICONDUCTORS
- WHAT IS IT?
- It acts both as a conductor and as an insulator; they have the ability to work "part-time"
- It's versatility lies on the fact that the conductivity can be controlled to produce effects such as:
- AMPLIFICATION
- RECTIFICATION
- OSCILLATION
- SIGNAL-MIXING
- SWITCHING
- WHAT ARE THE DIFFERENT TYPES OF SEMICONDUCTIORS?
- SILICON
- cheap and factory-made
- widely used in:
- diodes
- transistors
- integrated circuits
- GERMANIUM
- pure form is a poor conductor in electricity
- doped
- low voltage
- low resistance to heat; easily destroyed by it
- SELENIUM
- has a resistance that is dependent upon light
- photoconductivity
- photocells
- used in certain types of rectifiers
- can withstand brief transients and abnormally high surges of voltage
- GALLIUM ARSENIDE
- very expensive
- functions at high frequencies
- immune to ionizing radiation
- used in integrated circuits
- METAL OXIDES
- MOS
- CMOS
- draw so little current a battery lasts as long as its shelf life
- easily damaged by static electricity
- TRANSISTORS AND VACUUM TUBES AND INTEGRATED CIRCUITS
- VACUUM TUBES- used to be the backbone of electronic equipment; size ranges from the size of the thumb to that of the fist; sometimes it works better than transistors
- TRANSISTORS- smaller, easier to use; technology became smaller
- INTEGRATED CIRCUITS- came after transistors; can do the work of hundreds of vacuum tubes
- DOPING- the adding of impurities to alter the conductivity of the material
- acceptor impurities
- conducts by means of hole flow
- deficiency of electrons
- materials such as:
- indium
- aluminium
- boron
- gallium
- donor impurities
- conducts mainly by means of electron flow
- include:
- antimony
- arsenic
- bismuth
- phosphorus
- flow domination
- for donor impurities: electron flow dominates the current
- for acceptor impurities: hole flow dominates