In digital I/O terminology, when a gate output is at logic HIGH and can deliver current to an external load, this capability is referred to as the output's source current. Assess this definition.

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Digital outputs are characterized by how much current they can source (provide) at a HIGH level and sink (absorb) at a LOW level. Knowing the correct terms matters for interfacing logic devices and sizing pull-ups, LEDs, and other loads.


Given Data / Assumptions:

  • The statement defines source current for a HIGH output.
  • Standard TTL and CMOS push–pull outputs provide both sourcing and sinking capability within specified limits.
  • We are not discussing specialized outputs like open-collector (which cannot source in the active sense).


Concept / Approach:
“Source current” means current flowing out of the output pin into a load when the pin is at logic HIGH. Conversely, “sink current” is current flowing into the output pin from a load tied to Vcc when the pin is at logic LOW. Datasheets specify I_OH (source) and I_OL (sink) with corresponding guaranteed output voltages (V_OH, V_OL).


Step-by-Step Solution:
Check the definition: HIGH output delivering current → source current.Confirm against I/O conventions used in TTL/CMOS datasheets.Conclude the statement aligns with standard usage.


Verification / Alternative check:
Typical TTL specs: I_OH is smaller than I_OL, reflecting stronger sink capability; nonetheless, I_OH is the rated source current at logic HIGH.


Why Other Options Are Wrong:
Limiting it to open-collector or CMOS is inaccurate; the term is technology-agnostic. Logic level 12 V is unrelated to TTL/CMOS standard levels.


Common Pitfalls:
Confusing current direction; some beginners think “source” applies to LOW. Remember: source at HIGH, sink at LOW for push–pull drivers.


Final Answer:
Correct

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