Lab 2P. 1

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Digital Electronics

• Lab 2

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Analog Vs. Digital
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Analog Vs. Digital

• Analog
• Continuous
• Can take on any values in a given range
• Very susceptible to noise
• Digital
• Discrete
• Can only take on certain values in a given range
• Can be less susceptible to noise

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The Transistor

• Basic element of digital electronics
• Typically built into integrated circuits
• Can act like a switch

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Boolean Algebra

• Symbolic representation of logic statements
• Uses many basic arithmetic symbols , -, (), etc.

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Basic Logic Circuits AND
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Basic Logic Circuits OR
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Basic Logic Circuits NOT
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Basic Logic Circuits NAND

• NAND not AND
• Commonly used to implement other logic circuits

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Basic Logic Circuits NOR

• NOR not OR

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Integrated Circuits (Chips)

• A collection of many transistors, resistors, and
  capacitors on a single silicon wafer
• The wafer is mounted to a carrier for ease of use
  and dissipation of heat

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Prototype board for circuit layout
Terminal posts for power (red) and ground (black)
connections
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• Back side of Prototyping Board

Metal strips create electrically-connected holes
on the front
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Note the gaps where there are no electrical
connections
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Examples of electrically-connected holes
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And the corresponding gaps
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The channel is for ICs so that each pin will have
its own independent row of connected holes
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Light Emitting Diodes (LED)

• Function depends on orientation
• Pass electrical current in one direction only
• Illuminates when current is flowing through it
• Emits light proportional to current through diode
• Must have current limited by a resistor in series

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Power MOSFETs

• Allows control of high current DC loads by
  low-voltage digital signals
• With a 1 signal at the gate, current may flow
  from drain to source. Otherwise, the path is
  closed

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Laying Out the Circuit

• Chips bridge the gaps
• Devices in adjacent horizontal rows are connected
• Make sure power is turned off until circuit is
  finished!

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Todays Goals

• Build digital circuits on your breadboards and
  determine their function
• Test the Mystery Circuit
• Build a circuit to operate a motor with a power
  MOSFET