Digital Logic Flashcards
7 cards from real GATE 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 flashcards as text
Which of the following correctly describes a tri-state buffer?
Answer: Can output 0, 1, or high-impedance
A tri-state buffer outputs logic 0, logic 1, or high-impedance (Z) depending on its enable signal.
The hexadecimal number 2F is equivalent to which decimal value?
Answer: 47
2F hex = 2×16 + 15 = 32 + 15 = 47 in decimal.
A Moore machine's output depends on:
Answer: Current state only
In a Moore machine, outputs are a function of the current state alone, not the inputs.
What is the minimum number of flip-flops needed to build a MOD-10 counter?
Answer: 4
MOD-10 requires 10 states; since 2^3=8 < 10 ≤ 2^4=16, at least 4 flip-flops are needed.
Which of the following combinational circuits selects one of many inputs and routes it to a single output?
Answer: Multiplexer
A multiplexer (MUX) selects one of multiple input lines and forwards it to a single output based on select signals.
In a priority encoder with 4 inputs (I0–I3, I3 highest priority), if I1=1 and I3=1, what is the 2-bit output?
Answer: 11
Since I3 has the highest priority and I3=1, the encoder outputs 11 (encoding input 3).
Which flip-flop is commonly used as the basic building block in shift registers?
Answer: D flip-flop
D flip-flops are the standard choice for shift registers because the output directly follows the D input on each clock edge.