Digital Logic and Design Flashcards
7 cards from real BEE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Digital Logic and Design flashcards as text
Which Boolean identity is known as De Morgan's first theorem?
Answer: (A · B)' = A' + B'
De Morgan's first theorem states that the complement of a product equals the sum of complements: (A·B)' = A' + B'.
In a JK flip-flop, which input combination causes the output to toggle?
Answer: J=1, K=1
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.
A 4-bit magnitude comparator compares two 4-bit numbers A and B. How many output pins does it typically have?
Answer: 3
A standard 4-bit magnitude comparator (e.g., 74HC85) has three outputs: A>B, A=B, and A<B.
What does the term 'propagation delay' refer to in a logic gate?
Answer: The time between an input change and the resulting output change
Propagation delay (tpd) is the time interval between a specified input transition and the corresponding output transition of a logic gate.
Which type of ROM is electrically erasable and reprogrammable using byte-level erase operations?
Answer: EEPROM
EEPROM (Electrically Erasable Programmable ROM) can be erased and reprogrammed electrically at the byte level without UV light.
In a PLA (Programmable Logic Array), which two planes are programmable?
Answer: AND plane and OR plane
A PLA has both a programmable AND plane (for product terms) and a programmable OR plane (for sum of products), offering maximum flexibility.
What is the minimum number of NAND gates required to implement a 2-input XNOR function?
Answer: 5
A 2-input XNOR using only NAND gates requires 5 NAND gates, first implementing XOR with 4 gates and then inverting with a 5th.