Two Marks Questions with Answers

Two Marks Questions with Answers

Q.1 What are hazards ?

Ans. : The unwanted switching transients (glitches) that may appear at the output of a circuit are called Hazards.

Q.2 What are the two types of hazards ?

Ans. : The two types of hazards are :

1. Static hazard

2. Dynamic hazard.

Q.3 What is static hazard ?

Ans. : A static hazard exists if a signal is supposed to remain at particular logic value when an input variable changes its value, but instead the signal undergoes a momentary change in its required value.

Q.4 What are static-0 and static-1 hazards ?

AU : May-13, 15

Ans. : In a combinational circuit, if output goes momentarily 0 when it should remain a 1, the hazard is known as static-1 hazard. On the other hand, if output goes momentarily 1 when it should remain a 0, the hazard is known as static-0 hazard.

Q.5 Explain dynamic hazard.

Ans. : The hazard in which output changes three or more times when it should change from 1 to 0 or from 0 to 1 is called dynamic hazard.

Q.6 What is the cause of essential hazard ?

AU : May-03, 12, Dec.-04

Ans. : An essential hazard is caused by unequal delays along two or more paths that originate from the same input. Such hazards can be eliminated by adjusting the amount of delays in the affected path.