In studying digital integrated circuits, one must start with the simplest group of circuit, the SSIs...
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BASIC LOGIC GATES
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Transcript of In studying digital integrated circuits, one must start with the simplest group of circuit, the SSIs...
BASIC LOGIC GATES
In studying digital integrated circuits, one must start with the simplest group of circuit, the SSIs or Small Scale Integrated Circuits. Since these devices contain only a maximum of 10 transistorized components inside, these chips normally contain a function used in boolean algebra. Switching functions using boolean algebra is the simplest operation used in digital circuits, since it only involves a zero (0) and a one (1) much like the false (if zero) and true (if one) signals of boolean algebra
THE NOT GATE This type of gate accepts a single input
(either a logic ‘0’ or a logic ‘1’) and inverts the signal.
YA
The truth table for that gate is summarized as follows:
In equation form Y = A
INPUT(A)
OUTPUT(Y)
‘0’ ‘1’
‘1’ ‘0’
THE AND GATE This type of gate has two or more
inputs, and if we follow simple logic, this implies the statement if any among the list is false, then the expression is false.
The truth table for that gate is summarized as follows:
In equation form Y = A ● B One can extend this to n inputs by using
the following equation Y = A ● B ● C …….
AND GATEINPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘0’
‘0’ ‘1’ ‘0’
‘1’ ‘0’ ‘0’
‘1’ ‘1’ ‘1’
THE OR GATE This is type of gate has two or more
inputs, and if we follow simple logic, this implies the statement if any among the list is true, then the expression is true.
A
B
Y
The truth table for that gate is summarized as follows:
In equation form Y = A + B One can extend this to n inputs by using
the following equation Y = A + B + C …….
INPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘0’
‘0’ ‘1’ ‘1’
‘1’ ‘0’ ‘1’
‘1’ ‘1’ ‘1’
THE NAND GATE This type of gate has two or more
inputs, and it does the opposite of the AND gate. if any among the list is false, then the expression is true.
The truth table for that gate is summarized as follows:
In equation form Y = A ● B One can extend this to n inputs by using
the following equation Y = A ● B ● C …….
INPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘1’
‘0’ ‘1’ ‘1’
‘1’ ‘0’ ‘1’
‘1’ ‘1’ ‘0’
THE NOR GATE This type of gate has two or more
inputs, and it does the opposite of OR. if any among the list is true, then the expression is false
The truth table for that gate is summarized as follows:
In equation form Y = A + B One can extend this to n inputs by using
the following equation Y = A + B + C …….
INPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘0’
‘0’ ‘1’ ‘0’
‘1’ ‘0’’ ‘0’
‘1’ ‘1’ ‘0’
THE XOR GATE This type of gate has two or more
inputs, and it follows the exclusive OR Logic. This mean if the inputs are similar, the output is ‘0’. If the inputs are not similar then the output is ‘1’.
The truth table for that gate is summarized as follows:
In equation form Y = A B One can extend this to n inputs by using
the following equation Y = A B C …….
INPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘0’
‘0’ ‘1’ ‘1’
‘1’ ‘0’ ‘1’
‘1’ ‘1’ ‘0’
THE XNOR GATE This type of gate has two or more
inputs, and it does the opposite or XOR. This mean if the inputs are not similar, the output is ‘0’. If the inputs are similar then the output is ‘1’.
The truth table for that gate is summarized as follows:
In equation form Y = A B One can extend this to n inputs by using
the following equation Y = A B C …….
INPUT(A)
INPUT(B)
OUTPUT(Y)
‘0’ ‘0’ ‘1’
‘0’ ‘1’ ‘0’
‘1’ ‘0’ ‘0’
‘1’ ‘1’ ’1’
EXAMPLE
