DIGITAL ELECTRONICS DIGITAL ELECTRONICS Digital Logic Everything in

DIGITAL ELECTRONICS

DIGITAL ELECTRONICS Digital Logic • Everything in digital world is based on binary system. • Numerically it involves only two symbols 0 or 1. – 0 = False = No – 1 = True = Yes • Binary Number System : Easy to design stable electronic circuits.

DIGITAL ELECTRONICS Boolean Algebra • Digital circuits need to be as simple as possible. • Complex logical expressions should be reduced to simpler expressions, however, produce same results under all conditions. • Benefit: Simpler expressions can be implemented with simpler circuits, which are cost effective.

DIGITAL ELECTRONICS Boolean Algebra • Mathematics of logical expression is the tool to reduce the complicated expressions. • Introduced by George Boole in 1854 and known today as Boolean Algebra. • The rules of Boolean Algebra is simple and straightforward, can be applied to any logical expression.

DIGITAL ELECTRONICS Boolean Algebra • For two binary variables (taking 0 and 1), there are 16 possible functions. • These functions involve only three operations:

DIGITAL ELECTRONICS 16 Functions

DIGITAL ELECTRONICS Boolean Algebra Theorems

DIGITAL ELECTRONICS Gates • Gates are fundamental building blocks of digital logic circuitry. • These devices operate by “closing” or “opening” to admit or reject the passage of logical signal.

DIGITAL ELECTRONICS • Basic gate types are – AND – OR – XOR – NOT • A vast array of gating functions can be created from these basic gates.

DIGITAL ELECTRONICS The AND Gate Truth Table

DIGITAL ELECTRONICS The AND Gate Truth Table

DIGITAL ELECTRONICS +6 V IC 7408 Ground