MSI Logic Circuits Questions

• 74LS138 enables — The octal decoder’s outputs are enabled (active LOW) only for which specific enable-input combination?
• 74LS138 decode index — Evaluate: “With A0 = 1, A1 = 1, A2 = 0 (device enabled), output 3 is the selected line.”
• Multiplexer sizing — Evaluate: “A four-line multiplexer must have four data inputs and two select inputs.”
• 74LS139 as demultiplexer — The dual 2-to-4 decoder (74139) functions as a demultiplexer when the data is applied to which pin function?
• 74LS138 enable logic — The decoder’s outputs become active (LOW) when which enable-input combination is present?
• 74LS151 (8-to-1 multiplexer) select code: To route data input I1 to the output of a 74151/74LS151 eight-line multiplexer, what 3-bit select input code must be applied (assume the active-low enable /G is asserted low)?
• 74148 (8-to-3 priority encoder): When data input I5 is the asserted (active) input on a 74148 priority encoder, the three data outputs (A2, A1, A0) are claimed to be A0 = 1, A1 = 0, A2 = 0. Decide if this statement is correct (assume standard active-low inputs and outputs).
• Display technology suitability: “Incandescent 7-segment displays are especially well suited for portable, battery-operated devices.” Evaluate this claim considering power, efficiency, and durability.
• 74148 (8-to-3 priority encoder): When data input I4 is the asserted (active) input on a 74148 priority encoder, the data outputs are stated as A0 = 1, A1 = 1, A2 = 0. Decide if this statement is correct (assume standard active-low inputs/outputs).
• HDL description of a demultiplexer (DEMUX): In hardware description languages (e.g., VHDL/Verilog), which construct best and most exactly describes DEMUX behavior (one input routed to one of many outputs under select control)?
• HDL methods for unique output per input combination: For an application such as an encoder, where the circuit must produce a unique output for each input combination, which two description methods are most suitable in HDL?
• AHDL comparator coding style: A typical AHDL (or HDL) magnitude comparator follows an algorithm most naturally expressed using which construct?
• Magnitude comparator outputs (figure-based): For the shown binary inputs P and Q (figure not provided here), the three comparator outputs for P > Q, P = Q, and P < Q are requested, in that order. Choose the most plausible one-hot pattern (Recovery-First applied).
• Common interconnect terminology in computers: In most modern computers, bulk data transfers move over a shared set of conductors known as the ________.
• Definition check: A ________ is a combinational circuit that compares two binary quantities and asserts outputs indicating which operand has the greater magnitude (greater-than, equal-to, or less-than).
• 74LS151 / 74151 eight-to-one multiplexer (MSI logic): To select data input I5, what binary pattern must be applied to the select inputs (S2, S1, S0)? Assume the active-low enable (/G) is asserted (LOW) so the device is enabled.
• Display technologies in MSI/SSI interfacing: Which display type controls the reflection of available ambient light rather than emitting light by itself?
• Priority encoder 74148 (octal-to-binary, active-low): When input I6 is the active request, what is the 3-bit data output (Y2 Y1 Y0)? Assume the device follows standard 74148 conventions: inputs active LOW, outputs active LOW, and I7 has the highest priority.
• Real-world analogy for a multiplexer (data selector): Which everyday control most closely illustrates the function of a multiplexer by selecting exactly one of several available signal sources to pass onward?
• Using a 74139 dual 2-to-4 demultiplexer as a decoder: Under what condition does the 74139 behave like a one-of-four decoder that drives exactly one active output line?