# Basic Logic Circuits

### What is Logic Circuit?

Logic Circuit and Design is a tool for Computer Engineers, Electrical, Electronic Communication engineers and to those who wants to learn logic circuit design. Learning Logic Circuits and design should learn first the basic of it and this is the Function and symbols and all its individual characteristics. Logic Circuit can be use to evaluate complex database design into more effective and simple design. Truth table is one of the associated tools that is being used together with the logic design some of its associated tools are the “Boolean Algebra” or “Mathematical Logic“, “Karnaugh Map” or “K-Map” these are some of the tools that you can use, later we will discussed all about it. Logic is represented by a Binary Digits “1″ and “0″ corresponding to “True” and “False”, A “True” is a fact or reality and the “False” is its opposite. The Binary Digits can be represented by True or False, since that a machine can only understand a machine code (a system of instructions and data executed directly by a computer‘s central processing unit.), A True or False is the best way to represent binary. A True or Logic One is nearly equivalent to positive Five Volts DC(+5V), or simply called a Digital Signal. Table 1 shows the symbols and basic functions of a logic gate.

### And the table 2:

### Additional Informations

The Above tables shows each gate symbols and its Truth table. The

*gate, function as when one of its input is a Logic Zero “***AND***Low*” the resulting output is always a zero. The Logic Zero or “*Low*” is nearly equivalent to zero volt. The*Gate is conversely equivalent of***OR***Gate, Since that when one of its input is Logic one “***AND***high*” the resulting output is always a Logic one “high” no matter what are the values of the other input thus it can purposely assume the result as “high”. The NOT gate or an inverter takes only one input and as well as one output and its function is always a negation to the input. When the input is high the output is low and vice versa. The Gates in table 1 are special Logic Symbols, the*Gate negates the output of an***NAND***gate, and also the***AND***Gate negates the output of an***NOR***gate, meaning it inverts that’s why there is an inverter at the end of its symbol. The Most especial of them all are the***OR***or***XOR***(Exclusive OR) the function is if the two input of an gate are not the same (Zero and the other is one) the result is always “high” and if the two input are the same logic one the result is Logic one ‘High”, thus if the input are both zero the output is zero. That’s why this logic gate makes a very special gate. In**Gate (Exclusive Not OR gate) if the input are the same may it be zero or logic one the output is always logic one “high” and if it is not the same the result is zero. All the function of each gate can be evaluated in a truth table as shown in the table 1 and table 2.***XNOR**