There are two basic designs of logical circuits
Our interest is only in Combinational circuits and there applications. There are following steps to design combinational circuits.
1-Find number of inputs/outputs from problem statement.
2-Assign different letters to inputs and outputs e.g X,Y,Z,a,b,c etc.
3-Write truth table of problem.
4-Write simplified Boolean’s equation from truth table for each output.
5-Implement the circuit.
is a combinational logic circuit if there are 2^n input lines they will produce n number of outputs. There are following encoder combinations
1) 4 : 2 Encoder
2) 8 : 3 Encoder
3)16 : 4 Encoder
Q1 = D2 + D3
Q0 = D1 + D3
is totally opposite to encoder which have n number of inputs and provide us 2^n number of outputs. If we have 3 inputs D0 , D1 , D2 and there preference started from left to right when all are 0 then output is also zero but when the input is 1 then we can see output 1 showing result and then so on.
There are following decoder combinations
1)1 : 2 Decoder
2)2 : 4 Decoder
3)3 : 8 Decoder
2*4 decoder have 2 inputs and 4 outputs. Decoders are also used in 7-segment display.
As the name stated it depends upon priority function. If the two or more inputs have input 1 at the same time, the input having highest priority will take precedence.