Digital Systems & PLCs Quiz

What is the main difference between combinational and sequential circuits?

• Combinational circuits have storage elements, while sequential circuits do not.

• Combinational circuits have feedback paths, while sequential circuits do not.

• Combinational circuits depend on past inputs, while sequential circuits do not.

• Combinational circuits have outputs determined only by present inputs, while sequential circuits depend on both present and past inputs.

What is the purpose of a combinational circuit?

• To store and process data

• To perform operations based on present inputs

• To employ storage elements in addition to logic gates

• To depend on past inputs for output

How many possible binary input combinations are there for a circuit with n input variables?

• 2^n

• n!

• n^2

• 2n

What is the purpose of a decoder in digital systems?

• To select binary information from one of many input lines and direct it to a single output line

• To perform the inverse operation of a decoder

• To generate the arithmetic sum of three bits

• To convert binary information from n input lines to 2n unique output lines

What is the function of a priority encoder?

• To select binary information from one of many input lines and direct it to a single output line

• To ensure that only one input is encoded when two or more inputs are equal to 1 at the same time

• To provide the 2n minterms of n input variables

• To generate the arithmetic sum of three bits

What is the operation of a multiplexer?

• To convert binary information from n input lines to 2n unique output lines

• To perform the inverse operation of a decoder

• To select binary information from one of many input lines and direct it to a single output line

• To generate the arithmetic sum of three bits

What is the main purpose of a full adder circuit?

• To perform operations based on present inputs

• To store and process data

• To convert binary information from n input lines to 2n unique output lines

• To generate the arithmetic sum of three bits

What is the output of a full adder when all input bits are 0?

• 0

• 1

• 10

• 11

What is the function of the enable input in a decoder?

• To generate the arithmetic sum of three bits

• To convert binary information from n input lines to 2n unique output lines

• To ensure that only one input is encoded when two or more inputs are equal to 1 at the same time

• To disable the circuit when the enable input is 1

What is the purpose of a half adder circuit?

• To convert binary information from n input lines to 2n unique output lines

• To store and process data

• To perform operations based on present inputs

• To generate the arithmetic sum of two bits