Electronics Club

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Electronics Club

• Introductory Lecture on Digital Electronics

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Why Learn Digital ??

• Is it because computers are digital or the world
  is going Digital ??
• As Samsung says The new realm of DigitAll
  Technology
• One to One functions
• Virtually immune to noise
• Easy to rectify mistakes ( Why?? )

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What is Digital Electronics??

• A Digital circuit is based on a number of
  discrete voltage levels, as distinct from an
  analog circuit that uses continuous voltages to
  represent variables directly.
• In most cases the number of states is two, and
  these states are represented by two voltage
  levels one near to zero volts and one at a
  higher level depending on the supply voltage in
  use.
• These 2 discrete states might be called Low and
  High, 1 or 0 , True or False.
• Simple intuitive Boolean algebra !!!!

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Wanna See Noise Immunity !!
Technology Low Level High Level Supply Voltage
CMOS 0 to Vcc/2 Vcc/2 to Vcc Vcc 5V
TTL 0 to 0.8V 2V to Vcc Vcc 5V
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What is common to Digital Circuits??

• Supply Voltage ? 5V (at the club )
• A term called CLOCK

Will you change Mr. Logical One
Mr. Clock Says
Yes Sir !! Right away
Mr. Logical One Responds
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In Electronics Terms

• A clock is simply a square wave , which is mostly
  common to all components put in a digital
  circuit. We may classify it as a parameter in
  measuring speed of the circuit.

A Logical One
5V 0V
A Logical Zero
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The Binary Number System

• Representing Nos. as a sequence of 1s and 0s.
• Nos. in Base 2
• Decimal to Binary Conversion
• Binary to Decimal Conversion
• Intuitivism here too!!!!

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Logic Gates

• Simple Boolean functions
• AND
• OR
• NOT
• XOR
• NAND
• NOR

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AND Gate
Input 1(A) Input 2(B)
Output (Y)
Input 1 Input 2 Output
0 0 0
0 1 0
1 0 0
1 1 1
Y A B
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OR Gate
Input 1 (A) Input 2 (B)
Output (Y)
Input 1 Input 2 Output
0 0 0
0 1 1
1 0 1
1 1 1
Y A B
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NOT Gate
Input A
Output Y
Input Output
1 0
0 1
Y A
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XOR NOR NAND XNOR Gates
A B A XOR B
0 0 0
0 1 1
1 0 1
1 1 0
A B (AB)
0 0 1
0 1 1
1 0 1
1 1 0
A B A XNOR B
0 0 1
0 1 0
1 0 0
1 1 1
A B (AB)
0 0 1
0 1 0
1 0 0
1 1 0
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Dear Transistor

• Most simple use as a switch

Supply
Load Device
Input
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You did not understand something ???

• Read the handout
• Even better come to the workshop
• Lets work One to One ?
• Register for the workshop
• Finally Be there !!!!

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Thank You