Digital Logic and Systems 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 Systems flashcards as text
Which Boolean identity represents De Morgan's theorem for a two-input AND gate?
Answer: (AB)' = A' + B'
De Morgan's theorem states that the complement of a product equals the sum of complements: (AB)' = A' + B'.
What is the main advantage of a carry look-ahead adder over a ripple carry adder?
Answer: Computes carries in parallel, reducing addition time
Carry look-ahead adders generate and propagate carry signals in parallel rather than waiting for them to ripple through each stage.
A full adder differs from a half adder in that it:
Answer: Includes a carry-in input
A full adder has three inputs — A, B, and carry-in (Cin) — allowing it to be cascaded to build multi-bit adders.
Which state minimization concept groups equivalent states in a finite state machine to reduce hardware?
Answer: State reduction (state equivalence)
State reduction identifies and merges states that produce identical outputs for all input combinations, minimizing the number of flip-flops needed.
In Boolean algebra, which law states that A + AB = A?
Answer: Absorption law
The absorption law states A + AB = A because A already implies AB, so the redundant term AB is absorbed.
A synchronous counter differs from an asynchronous (ripple) counter in that:
Answer: All flip-flops are clocked simultaneously
In a synchronous counter, all flip-flops share the same clock signal, eliminating cumulative propagation delays present in ripple counters.
Which type of programmable logic device consists of a programmable AND array followed by a fixed OR array?
Answer: PAL (Programmable Array Logic)
A PAL has a programmable AND plane and a fixed OR plane, making it simpler and faster than a PLA but less flexible.