BEE Digital Logic and Design 3

Question 1

Which Boolean identity is known as De Morgan's first theorem?

Accepted Answer

(A · B)' = A' + B'

Answer

De Morgan's first theorem states that the complement of a product equals the sum of complements: (A·B)' = A' + B'.

Question 2

In a JK flip-flop, which input combination causes the output to toggle?

Accepted Answer

J=1, K=1

Answer

When both J=1 and K=1, the JK flip-flop toggles its output on each active clock edge, resolving the indeterminate state of the SR flip-flop.

Question 3

A 4-bit magnitude comparator compares two 4-bit numbers A and B. How many output pins does it typically have?

Accepted Answer

3

Answer

A standard 4-bit magnitude comparator (e.g., 74HC85) has three outputs: A>B, A=B, and A<B.

Question 4

What does the term 'propagation delay' refer to in a logic gate?

Accepted Answer

The time between an input change and the resulting output change

Answer

Propagation delay (tpd) is the time interval between a specified input transition and the corresponding output transition of a logic gate.

Question 5

Which type of ROM is electrically erasable and reprogrammable using byte-level erase operations?

Accepted Answer

EEPROM

Answer

EEPROM (Electrically Erasable Programmable ROM) can be erased and reprogrammed electrically at the byte level without UV light.

BEE - Bachelor of Electrical Engineering Practice Test