Adder and Subtractor Test

1. The inverter can be produced with how many NAND gates?

2. How many NOT gates are required to implement the Boolean expression: X = AB'C + A'BC?

3. How many shift registers are used in a 4 bit serial adder?

4. What is ripple carry adder?

The carry input of the lower order stage is connected to the carry output of the next higher order stage

The carry input of the higher order stage is connected to the carry output of the lower order stage

The carry output of the higher order stage is connected to the carry input of the next lower order stage

The carry output of the lower order stage is connected to the carry input of the next higher order stage

5. A D flip-flop is used in a 4-bit serial adder, why?

It is used to store the sum output of the full adder

It is used to store the carry output of the full adder

It is used to invert the input of the full adder

It is used to store the output of the full adder

6. If minuend = 0, subtrahend = 1 and borrow input = 1 in a full subtractor then the borrow output will be __________

Floating

High Impedance

7. What are carry generate combinations?

If all of the output are independent of the inputs

If all of the input are dependent on the output

If all of the output are dependent on the input

If all the input are same then a carry is generated

8. The carry look ahead adder is based on the principle of looking at the lower order bits of ________ and ________ if a high order carry is generated.

Addend, minuend

Augend, addend

Addend, minuend

Minuend, subtrahend

9. In serial addition, the addition is carried out __________

Bit by bit

3 bit per second

All bits at the same time

Byte by byte

10. One positive pulse with tw = 75 µs is applied to one of the inputs of an exclusive-OR circuit. A second positive pulse with tw = 15 µs is applied to the other input beginning 20 µs after the leading edge of the first pulse. Which statement describes the output's relation with the inputs?

The exclusive-OR output is a 20 s pulse followed by a 40 s pulse, with a separation of 15 s between the pulses

The exclusive-OR output is a 15 s pulse followed by a 40 s pulse

The exclusive-OR output is a 20 s pulse followed by a 15 s pulse, followed by a 40 s pulse

The exclusive-OR output is a 20 s pulse followed by a 15 s pulse, with a separation of 40 s between the pulses