Chapter 16 Flashcards
What does CRT stand for
Cathode ray tubes
How do cathode ray tubes work
Electrons start flowing flowing to the positively charged side/rod. When they hit the metal it completes a D.C. circuit some electrons however miss the rod and hit a photochemical coating and the electrons make the coating glow and the target casts a shadow
What would happen if a high energy generator to power the cathode ray tubes
X-rays would come off the target you could angle the tweeter do it shoots the X-rays in different directions. This is the basis of X-rays
Diodes
Produces radio waves and static
Triode
Developed into Morse code when you turn it on or off it sends signals. It has 3 electrodes and a small charge you can start or stop the flow with the 3rd middle triode
Why re cathode ray tubes an old things of the past
Semiconductors
NPN JUNCTIONS
One way bridge description of transistors
NPN junctions became what
Language binary code of all computers (0 and 1 or on/off)
How do you create messages
If you have millions of some on some off junctions you can creat messages
Millions of junctions
Processes
Every letter we type is translated
To a series of 0s and 1s
Inventor of silicon chip transistor
Bell Labs
Light emitting diodes
LED transistors that create resistance and put out light
Photovoltaic solar cells are put on what kind of fields
Brown fields
What are photovoltaic cells made of and why
Silicon crystals bc when sun hits the silicon atoms an electron is kicked off
Explain how integrated circuits are made
Ovens make pure silicon by melting silicon. It condenses and forms a huge crystal they cut the crystal into silicon wafers. The process is mostly robotic so humans don’t deposit dust. A gigantic photograph is minimized and projected onto the silicon the silicon is coated with chemicals called a photo mask that react when light hits them. Lasers carve they rinse and repeat
Transistors
Structures of Silicon lasers carve
Texas instrument
The ones who created the first calculators with integrated circuit chips
Where do they integrated circuit chips
Class one clean rooms so no dust comes in no dust can be in pure Sì
Moore’s Law
About two years you can double the number of transistors on the same size integrated
Double the transistors
Double the speed the computer runs
Charles Babbage
1st to design me mechanical calculators like the adding machine
Slide rule
3 pieces of bamboo that slide back and forth and could calculate to three decimal points
ENIAC
1946, first computer.
Purpose= to do calculations to find out if nuclear weapons were possible. Huge very basic with 5000 calculations per sec
It had no way to store information
What made the first computer possible
The deforest triode tube
UNIVAC
Computer like ENIAC but could store information on big magnetised tapes 1950s
Bit
Either a 0 or 1 Binary digIT
Byte
8 digits has up to 256 possibilities
Kilobyte
1024 bytes
Megabyte
1,048,576 bytes
ASCII
1st programming language
C++
Most common programming language used today very sophisticated
Why is it cheaper to make desktops rather than laptops
It costs more to make everything smaller
ROM
Read only memory permanent memory
RAM
Random access memory temporary memory
Computer uses it to hole info while it’s processing
Has gold on it so it doesn’t oxidize
What is the battery in a computer used for
Maintaining clock and time and basic info for computer
What is the power supply in PC
Step down transformer goes from 120 V to 12-24 V there is a fan to cool it
Hard drive
Magnetized to hold permanent info can be replaced
Flash Drives
Typically 120 MB they are a good way to back up info
Server cited computing
Aka cloud computing. A company on the internet backs up info for you advantages are you won’t lose info if a fire occurs at your house it’s an easy way to back up and computers don’t have to be as powerful but there’s no privacy
Client cited computing
Computer does all backing up
Redundant servers
They’re saving info at two separate locations for you in case something happens to the one location with your info
Input devices
Keyboard, mouse, microphones =primary ways to input info into computer
Output devices
Monitors and speakers; the way to receive information
LAN
Local area network
WAN
Wide area network
Mainframe computers
Large versions of computers they can process faster and have much more memory
Who started the internet
A US government agency called DARPA IN the 1980s
Supercomputers
Essentially a lot of mainframe computers that dispense info to cell phones and computers
