Logic Circuits and Boolean Algebra

Question 1

What are the 2 outputs of a half-adder.

Answer 1

-Sum bit (xor gate)
-Carry bit(and gate)

Question 2

What are the 2 outputs of a full-adder.

Answer 2

-Sum bit (xor gate)
-Carry bit(or gate)

Question 3

What are flip-flops?

Answer 3

-They are circuits/ electronic components.
-With two states
-USed for data storage
… to store one bit of data.

Question 4

Difference between SR and JK flip-flop.

Answer 4

-SR flip-flop has undefined / invalid / indeterminate state // JK flip-flop is stable
-JK flip flop has a clock pulse

Question 5

SR flip-flop. What are the two inputs and what gates is it constructed with.

Answer 5

-Inputs are R/Reset and S/set.
-Can be constructed using two NAND gates or two NOR gates.

Question 6

Purpose of an SR FlipFlop

Answer 6

-Use to store a binary digit.

Question 7

Why is the JK flip-flop an improvement to the SR flip-flop?

Answer 7

-The SR flip-flop has an invalid combination of SR which allows Q and notQ to have the same value.
-The JK flip-flop does not allow Q and notQ to have the same value.

Question 8

Advantages of JK flip-flop

Answer 8

-All four possibilities are valid.
-The 1-1 combination changes output to logical complement.
-Unstable state avoided.
-Invalid state cannot occur.