Transistor

• Invented at Bell Labs in 1947
• Device that acts either:
  • Wire conducting electricity
  • Resistor that blocks the flow of electricity
  • Depends on voltage level of an input signal
• No moving parts
• Acts like a switch
  • Either on or off
  • Takes a few nanoseconds to switch states
• Made of a semiconductor material
  • Usually silicon
• Smaller than vacuum tubes and require less energy to operate
• Three terminals
  • Source
    • Usually the output line
    • Source signal pulled to ground --> output signal is low
    • Source signal remains high --> output signal is high
  • Base
    • Regulates a gate determining whether source and ground connect
    • Base signal high --> source signal grounded
    • Base signal low --> source signal high
  • Emitter
    • Typically connected to ground

Computer Science Electricity