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Day 3 |
Lab |
Vocabulary Test
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| Electronics: | The study of the release, behavior, and effects of electrons in useful devices. |
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Computers and televisions are powered by A.C. electricity, but most things happening inside them require D.C. electricity. What electronic component in them changes A.C. to D.C. electricity? |
Your understanding of electronics must begin with the vacuum tube. A vacuum tube is a sealed tube with a "gate" that allows electrons to travel in only one direction. Most of these tubes are glass, but not all. Vacuum tubes come in sizes ranging from less than an inch to
over a foot in length. They allow us to increase or decrease the energy of electrons, change the direction of electron flow, even switch the flow of electrons off and on.
Vacuum tubes operate at a very high temperature. They take from several seconds to several minutes to "warm up" to operating temperature. The tubes are subjected to thermal stress because of the heating and cooling involved in their use. The glass tubes are subject to breakage and all vacuum tubes are easily damaged by impacts. Electronic devices using vacuum tubes are large and hot running. The tubes have a fairly short lifespan, so devices using them require a lot of attention to keep them in top shape.
The development of the transistor
to replace vacuum tubes solved many of these problems. Transistor devices are much less expensive, smaller and more durable to operate. Their energy requirements are much lower and they operate at a cooler temperature. These advantages have caused transistors to replace vacuum tubes in most applications. The first transistors were 1/2 inch long. Today, millions of transistors fit on a rectangular "chip" only 1/2 inch on each side.
But don't think that vacuum tubes are no longer used. An Internet search for "vacuum tube" will return thousands of sites!
Electronic Components:
Test Your Concept Understanding: 
- Read this information bulletin
- How many transistors were in the first commercial transistor radio?
- In what two cities were these radios first sold to the public?
- Texas Instruments made the transistors, but not the radio itself. What "brand" was this radio?
- Start with this PBS webpage.
- What was J.J. Thomson's favorite toast?
- What communications technology was the first to make full use of the vacuum tube?
- What must atoms do to become superconductors?
- What quantum mechanics idea caused Albert Einstein to say, "God does not play dice with the universe"?
- The first "point contact transistors" needed two metal contacts separated by the thickness of a piece of paper. At the time, the smallest wires were almost three times that thick. How did Walter Brattain solve this problem?
- Use this webpage
- List three metals used in computer chips.
- Computer chips are built in layers. About how many layers are used to make a computer chip?
- What does the process of "doping" do to a computer chip?
Day 2
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Why do radio and television stations always locate their transmission towers so they are surrounded by open, flat land? |
Test Your Concept Understanding:
- List as many forms of "communication" as you can.
- Find out more about the development of the Internet.
- In what year did the first artificial satellite orbit the Earth?
- What percent of all network traffic was e-mail in 1973?
- "Mosaic" was the first internet "browser". In what year was it introduced?
- Read the New York Times story
- What was the date of the broadcast?
- What program was broadcast?
- How many cities received the broadcast?
- How many cameras were used in the broadcast?
- How big was the screen on the first color TVs?
- How much did these TVs cost?
Day 3
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How many "letters" are in a computer's alphabet? |
In twenty five years, personal computers advanced from the Altair 8800 on the right to multimedia laptops on the left. The input device of the Altair was a row of 8 toggle switches and output was from the 8 lights above the switches. There is absolutely no comparison between the precessing power of the two machines.
Computer Systems Analyst |
In 1963 the Royal Precision Vacuum Tube Computer contained 113 vacuum tubes, a drum memory disk and a paper tape reader and punch. This computer costs $50,000 at the time. In 1975, a kit for the Altair 8800 computer cost $397. The Altair 8800 was the first "personal" computer and had a memory of only 256 bytes. |
No matter the speed, size, or cost, all computers have four main "hardware" parts:
A computer is essentially a mass of switches. These switches are either "on" or "off". All the information and instructions in the computer is contained in these switches. Since there are only two possibilities for the position of a switch, the language of computers is "binary".
Terms related to computer language: 
When you make a keystroke on the keyboard, this code is the reason the CPU of your computer understands what you are telling it.
This assignment must be turned in by the beginning of class tomorrow to receive credit.
Scoring criteria
- What is the name of the "operating system" of your laptop computer?
- 5 Exabytes represents how many words?
- More about computer components:
- What does the ALU of a CPU do?
- Binary digits are "base 2". What "base" are octal digits?
- How are machine language and assembly language different?
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Any volunteers may ask your science facilitator for an "electronic device" to take apart. |
Research Links:
A rectifier changes A.C. to D.C. electricity in electronic devices.
