System integration with IC counters — should output devices (e.g., LEDs) be designed to operate from counter outputs? Judge the statement that, in a complete system built around counter ICs, output indicators must be interfaced to the counter outputs properly for correct operation.

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Turning a counter IC into a working application requires proper interfacing to displays, LEDs, or other loads. The statement emphasizes that outputs must be configured to drive the chosen indicators correctly—an obvious but vital systems point.



Given Data / Assumptions:

  • Counters present logic-level outputs representing count states.
  • Indicators (LEDs, seven-segment modules, etc.) require appropriate current limiting and polarity.
  • Power supply, fan-out, and timing constraints are respected.


Concept / Approach:
Correct operation requires matching logic output characteristics to load requirements: voltage levels, source/sink current capability, and whether the indicator is common-anode or common-cathode. Sometimes buffers or drivers (e.g., transistor arrays) are inserted to meet current needs or to translate voltage levels.



Step-by-Step Solution:

Determine output type: totem-pole, open-collector, or CMOS push-pull.Design LED interface: series resistor sizing, correct polarity, possible driver IC.Check timing: ensure indicators sample after stable transitions (or use latches/decoders).Integrate with power budget and thermal limits for reliability.


Verification / Alternative check:

Prototype on a bench: confirm brightness, logic correctness, and absence of ghosting or glitches.


Why Other Options Are Wrong:

Incorrect: Ignoring interfacing leads to under/over-drive and unreliable outputs.Only if synchronous / Only with open-collector: Interfacing is necessary regardless of counter style; specifics vary but the need persists.


Common Pitfalls:

Forgetting current-limiting resistors for LEDs.Assuming logic can source more current than the datasheet allows.


Final Answer:

Correct

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