Introduction to Electrical Engineering II

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Introduction to Electrical Engineering II
Logic Systems and Gates

• Prof. Dr. Hasan H. Erkaya
• Eskisehir Osmangazi University
• 2008

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Systems

• Analog Systema system in which variables are
  allowed to take any value within a range

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Analog Systems

• An electrical circuit

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Analog Systems

• Another electrical analog circuit

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Systems

• Digital Systema system in which variables are
  allowed to take only predetermined finite number
  of values

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Digital Systems
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Digital Systems

• Binary numbers are used to represent most digital
  systems.
• Binary digit bit ( 0, 1)
• 8 bits side by side 1 byte (e.g. 10011011)

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Binary Systems

• A physical variable is used to represent binary
  values e.g. a voltage or a current

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Binary Systems

• Analog to Digital Converter

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ADC
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Binary Systems

• Digital to Analog Converter

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DAC
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Why bother with digital systems?

• Digital sistems can process information a lot
  easier than analog sistems
• Digital computer is much more skilful than the
  analog computer
• Is there an analog computer, too?(Yes! It can
  take derivative, integral and do other operations)

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Boolean Algebra

• Basic OperationsANDORNOT
• Gates are used for these operations

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AND gate
A . B
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OR gate
AB
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NOT gate(inverter)
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Combined Gates

• AND NOT NAND
• OR NOT NOR

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Exclusive OR
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Exclusive NOR
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Logic Functions
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Truth Table
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Karnaugh Maps
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Karnaugh Maps
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K-maps
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Building the Circuit

• Often NAND gates are used to implement the logic
  functions

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7400 series ICs

• 7400 Quad 2-input NAND Gate
• 7401 Quad 2-input NAND Gate with Open Collector
  Outputs
• 7402 Quad 2-input NOR Gate
• 7403 Quad 2-input NAND Gate with Open Collector
  Outputs (different pinout than 7401)
• 7404 Hex Inverter
• 7405 Hex Inverter with Open Collector Outputs
• 7406 Hex Inverter Buffer/Driver with 30V Open
  Collector Outputs
• 7407 Hex Buffer/Driver with 30V Open Collector
  Outputs
• 7408 Quad 2-input AND Gate
• 7409 Quad 2-input AND Gate with Open Collector
  Outputs

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7400 series ICs

• 7410 Triple 3-input NAND Gate
• 7411 Triple 3-input AND Gate
• 7412 Triple 3-input NAND Gate with Open
  Collector Outputs
• 7413 Dual Schmitt trigger 4-input NAND Gate
• 7414 Hex Schmitt trigger Inverter
• 7415 Triple 3-input AND Gate with Open Collector
  Outputs
• 7416 Hex Inverter Buffer/Driver with 15V Open
  Collector Outputs
• 7417 Hex Buffer/Driver with 15V Open Collector
  Outputs
• 7419 Hex Schmitt trigger Inverter
• 7420 Dual 4-input NAND Gate
• 7421 Dual 4-input AND Gate
• 7422 Dual 4-Input NAND Gate with Open Collector
  Outputs
• 7423 Expandable Dual 4-input NOR Gate with
  Strobe
• 7424 Quad 2-input NAND Gate gates with
  Schmitt-trigger line-receiver inputs.
• 7425 Dual 4-input NOR Gate with Strobe

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7400 series ICs

• Flip-flops
• Counters
• Registers
• Memory devices
• and more

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7400 quad 2-input NAND gates
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7404 hex inverters
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7408 Quad 2-input AND gates.
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7410 Triple 3-input NAND gates
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8-input NAND gate
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7432 Quad 2-input OR gates
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Logic Circuits

• Combinational Logicoutput is determined by
  inputs only
• Sequential Logicoutput depends on the inputs
  and historyit contains some memory device to
  remember the past

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Logic Systems and Gates

• I hope this presentation gave you a glimpse of
  the logic systems and digital circuits.
• You will have plenty of experience with digital
  circuits in Digital Systems I, II and Lab
  courses.
• End of the presentation