Transistors, Analog, and Digital

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4/10/06 Transistors, Analog, and Digital

• Poster Session Meetings
• Schedule appointment
• Change/Modify your topic
• Plan your poster
• Etc.

• Wednesdays Reading
• Section 13.1 Radio (pp. 423 431)
• Upcoming Reading Assignments
• Section 13.2 Microwave Ovens (pp. 432 438)
• Section 14.1 Sunlight (pp. 445 453)
• Section 14.2 Discharge Lamps (pp. 454 463)
• Section 14.3 Lasers and LEDs (pp. 464 470)
• Section 15.1 Cameras (pp. 478 488)
• Section 15.2 Optical Recording and Communication
  (pp. 489 497)

Lab 9 this afternoon Bring N pole marked magnet
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• Capacitors
• Two closely spaced conducting plates
• Separated by a thin insulating layer
• Holds charge (equal and opposite, overall
  neutral)
• Potential difference between plates (charge,
  geometry)
• Applications
• Slows things down
• Stores Charge, Potential Difference
• Memory
• Keyboards

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Start with good insulator
Semi-conductors and p-n junction
Add small impurity that opens up some space
in the valence band P(ositive)-type or p-type
Add small impurity that add some electrons to
conduction band N(egative)-type or n-type
Taken from howstuffworks.com http//electronics.ho
wstuffworks.com/led1.htm
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Biasing the Junction
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• Diodes
• p-type semi-conductor joined to n-type
  semi-conductor
• p-n junction
• Results in depletion region
• Apply a potential difference across junction
  (like hooking up battery)
• Reverse bias ? increases depletion region
• Forward bias ? enough potential shrinks
  depletion region to nothing
• No depletion region means current can flow.
• So results in current flow in one direction!
• Resistors
• Resistance Rule (Ohms Law) Current
  proportional to voltage drop

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Power Adapter
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Transistors
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Transistors
n-channel MOSFET Metal-Oxide-Semiconductor Field
Effect Transistor
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Analog and Digital
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Memory RAM vs. ROM Volatile vs. Non-Volatile