lectures.alex.balgavy.eu

Lecture notes from university.
git clone git://git.alex.balgavy.eu/lectures.alex.balgavy.eu.git
Log | Files | Refs | Submodules

index.md (869B)


      1 +++
      2 title = 'Basic logic gates'
      3 +++
      4 # Basic logic gates
      5 Logic gates are transistor-based components. Here are the four basic ones.
      6 
      7 ## NOT (complement)
      8 
      9 for a variable x,
     10 x̄ = 1-x
     11 ∴ x + x̄ = 1
     12 
     13 ![screenshot.png](screenshot-28.png)
     14 
     15 ## OR (union)
     16 OR function (+) has value 1 if any of inputs has value 1.
     17 
     18 ![screenshot.png](screenshot-26.png)
     19 
     20 Properties:
     21 - 1 + x = 1
     22 - 0 + x = x
     23 
     24 ## AND (intersection)
     25 AND function (⋅) has value 1 if all inputs have value 1.
     26 
     27 NOTE: the operator ‘⋅’ is often omitted!
     28 
     29 ![screenshot.png](screenshot-29.png)
     30 
     31 Properties:
     32 - x₁ ⋅ x₂ = x₂ ⋅ x₁
     33 - 1 ⋅ x = x
     34 
     35 ## XOR (exclusive or)
     36 XOR function (⨁) has value 1 if one of inputs has value 1.
     37 
     38 ![screenshot.png](screenshot-27.png)
     39 
     40 - x₁ ⨁ x₂ = x₂ ⨁ x₁
     41 - 1 ⨁ x = x̄
     42 - 0 ⨁ x = x
     43 
     44 How an XOR gate is built and functions:
     45 
     46 ![circuit.gif](circuit.gif)