Truth Table is needed to show the output for all the possible inputs in a digital circuit.As Digital circuits are based on true(value 1) and false( value 0),it is same as truth table of boolean algebra.
All the permutations of inputs of a circuit is written on left hand side of the table and the outputs are written on right hand side.A simple binary half-adder circuit is given below-
All the permutations of inputs of a circuit is written on left hand side of the table and the outputs are written on right hand side.A simple binary half-adder circuit is given below-
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| Half-Adder Circuit |
The circuit has two inputs A and B. And the outputs are Sum(S) and Carry(C).We have to find all the permutation of values of A and B.From the above circuit we can find out the sum and carry part.
The equation for Sum is , S=A XOR B i.e. AB'+A'B
C=AB
The truth table will look like this-
Inputs
|
Outputs
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||
A
|
B
|
S=AB'+A'B
|
C=AB
|
0
|
0
|
0
|
0
|
0
|
1
|
1
|
0
|
1
|
0
|
1
|
0
|
1
|
1
|
0
|
1
|
Here we have found all the combinations of inputs and as we have the circuit we can have the output,as shown here.You can also draw the circuit if you have the truth table from the circuit.
Combinational Circut
Sequential Circuit
Number System
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