(i) What is a decoder? How is it different from a multiplexer? Draw the logic circuit
for a 2 to 4 decoder and explain its working.
(ii) Verify if the following proposition is valid:
( P => Q ) ∧ ( P => R ) = P => ( Q ∧ R )
(iii) Write the maxterm and minterm for the function F(A, B,C,D) when, A=1, B=1,
C=0 and D=1.
Solution
(i)
A decoder is a circuit which convert the binary number into its equivalent decimal form. In a decoder if there are 3 input lines it will be capable of producing 8 different outputs, one for each of the state which the 3 input can take.
A decoder accepts n input binary codes and converts them into a corresponding output signal, whereas a multiplexer select one of the several inputs and transmits the selected input signal to a single output.
