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Intro to Computer Science (ICS3U/C)
  • An Introduction to Computer Science
  • Videos & Slides
  • Unit 1: In the Beginning
    • The History of Computers
    • Binary & Logic
      • Bits and Bytes (Binary)
      • Transistors (Changing Bits)
      • Logic Gates
        • Poster
        • Logic.ly
    • The Parts of a Computer
  • Unit 2: Intro to Code
    • How Do We Code?
      • Coding Conventions (Rules)
      • Commenting Code
    • What is HTML?
      • Hello World! (in HTML)
      • HTML Slideshow
    • Hello World!
    • Input / Output
      • The Console
      • Prompt, Alert, Confirm
    • Variables & Data
      • Strings (Text)
      • Numbers (Values)
        • Converting & Rounding
        • The Math Object
          • Random Numbers
      • Booleans
        • Truthiness
      • Arrays
  • Unit 3: Control Flow
    • Conditionals (if this, do that)
      • If...Else
        • Logical Operators
      • Switch / Case
      • Ternary Operators
    • Loops (Repeating Code)
      • For...Loop
      • While & Do/While Loops
    • Debugging
  • Unit 4: Functions
    • Functional Programming
    • User Defined Functions
      • Hoisting and Scope
    • Calling a JS Function
  • TL;DR
    • Programming Basics
    • Slideshows & Demos
    • Javascript Syntax Poster
  • Advanced Topics
    • Recursion
    • Structures & Algorithms
    • Mmm... Pi
  • External Links
    • Typing Club!
    • repl.it
    • Khan Academy
    • Geek Reading
    • ECOO CS Contest
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  1. Unit 1: In the Beginning
  2. Binary & Logic

Transistors (Changing Bits)

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Last updated 4 years ago

The most important invention in the history of computers is (arguably) the transistor. A transistor can serve two purposes:

  • It can amplify a signal (transistor radio).

  • It can switch on and off ridiculously fast. This fast switching is what allows a computer to make decisions very fast.

Think of a transistor like a gate which either allows electricity through (1) or blocks it (0). If a small amount of electricity is applied to the base pin, whatever is on the collector pin is permitted through the emitter pin.

Consider this:

Transistors can be made as small as 10 nanometers10\text{ nanometers}10 nanometers . That's 0.00001 millimeters0.00001 \text{ millimeters}0.00001 millimeters. A typical sheet of white printer paper is about 280,000 nm280,000\text{ nm}280,000 nm thick yet a transistor can be made 10 nm10 \text{ nm}10 nm. They are so small that Apple's A11 chip in the iPhone X has 4.3 billion4.3 \text{ billion}4.3 billiontransistors yet it is only 88 mm288 \text{ mm}^288 mm2.

Controlling electricity like this gives us the ability to create boolean logic or .

logic gates
By commons.wikimedia.org/wiki/User:Inductiveload
When the base is "on" the electricity flows out the emitter