What is logic gates???
Logic gates represent a true or false expression.
The most common symbols used to represent a logic gates are NOT, AND, OR, NAND,
NOR, XOR.
Next is i'll show you what is truth table and from the logic symbol we can draw the truth table..
4.2 TRUTH TABLE
Truth tables are used to show logic gates functions.
It helps people to understand the behavior of logic gates. They show how the
input(s) of logic gate relate to its output(s). When constructing a truth
table, the binary values 1 and 0 are used. Every possible combination depending
on number of input is produced. Basically, the number of possible combinations
of 1s and 0s is 2^n where n equal to number of inputs.
4.3 DESCRIPTION OF THE SIX LOGIC GATES
NOT gate
- Produce an inversion version of an input at its output
- If the input variables is A, the inverted output fir A is known as NOT A shown as A' or A with bar over the top
- Algebraic expression, F = A' or F = !A
AND gate
- The output is true if both input are true.
- A dot (.) is represents the operation of AND gate.
- Algebraic expression, F = A.B or F = AB
OR gate
- The output is true if either one or more input true.
- A plus (+) is used to represents OR operation.
- Algebraic expression, F = A + B
NAND gate
- This is a NOT-AND gate which is equal to an AND gate followed by a NOT gate.
- The output is true if the inputs are not both true
- Algebraic expression, F = (A.B)'
NOR gate
- This is a NOT-OR gate which is equal to an OR gate followed by a NOT gate.
- The output is true if both inputs are not true.
- Algebraic expression, F = (A+B)'
XOR gate
- Implements an exclusive OR.
- The output is true if one, and only one, of the inputs to the gate is true.
- Algebraic expression, F = (A.B)' + (A.B)'
that's all for today, i'll show more next time...
by nadhiah amira nordin
< B031310415 >
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