BOOLEAN ALGEBRA
Foreword

### Audio

Logic links
Negation (NOT)
Product (AND)
Inverted Product (NAND)
Sum (OR)
Invertd Sum (NOR)
Exclusive sum (XOR)
Logical Functions
Sequential and combinatorial functions
Tables

# BOOLEAN ALGEBRA Boolean (George Boole 1815-1864) algebra considers functions of variables which can assume only two values:

True or False

Such values are generally associated with the following symbols:

1 (indicating True value)
0 (indicating False value)

In electrical circuits:
a variable may indicate the presence (positive logic) or the absence (negative logic)of a predetermined tension value.
Usually Boolean variables are identified with letters as: A.
The interaction between variables, determined by logic links (e.g. B is true if A is false ), is expressed by functions of the following type: Where is the negation of A ( i.e. is True if A is false).

Note:
The first application of Boolean algebra was in the railroad field where Boolean variables indicated the position of rail switches.