# Logic Circuits Questions and Answers

## Logic Circuits Questions and Answers

### Q1. What is a combinational circuit?

In a combinational circuit, the output depends upon present input(s) only i.e, not dependant on the previous input(s). The combinational circuit has no memory element. It consists of logic gates only.

### Q2. Write two characteristics of combinational circuits.

The two characteristics of combinational circuits are:

• In combinational circuits, the output exists as long as the input exists.
• A combinational circuit will always respond in the same fashion to the input function, when we apply signal to the input terminal of the combinational logic circuit.

### Q3. What is a half-adder?

A logic circuit, that can add two 1-bit numbers and produce outputs for sum and carry, is called a half-adder.

### Q4. What is a full-adder?

A binary adder, which can add two 1-bit binary numbers along with a carry bit and produces outputs for sum and carry is called a full-adder.

### Q5. What is a flip-flop?

A flip-flop is a basic memory element that is made of an assembly of logic gates and is used to store 1-bit of information.

### Q6. What is a latch?

It is a D-type of flip-flop and stores one bit of data.

### Q7. What is an excitation table?

Excitation table gives an information about what should be the flip-flop inputs if the outputs are specified before and after the clock pulses.

### Q8. What is a state table?

State table consists of complete information about present state, next state, and outputs of a sequential circuit.