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
