Naming the HIGH-state output current for a 7400 NAND gate The output current capability of a single 7400 NAND gate in the HIGH state is referred to as:

Introduction / Context:
Datasheets specify output current capabilities separately for HIGH and LOW states. The conventional symbols are IOH for the HIGH-state output current (positive current sourced by the output) and IOL for the LOW-state output current (current sunk into the output). Knowing these terms is essential when computing fan-out and selecting pull-ups or loads.

Given Data / Assumptions:

• Part family: TTL 7400 NAND gate.
• HIGH-state current naming convention: IOH.
• LOW-state current naming convention: IOL.

Concept / Approach:

When the output is HIGH, a TTL gate can typically source only a small current (IOH), while it can sink a larger current when LOW (IOL). This asymmetry impacts interfacing and pull-up sizing in mixed-technology systems.

Step-by-Step Solution:

Verification / Alternative check:

Consult any standard TTL datasheet: the tables list VOH with IOH and VOL with IOL constraints.

Why Other Options Are Wrong:

“Source current” is descriptive but not the exact symbol; “sink current”/IOL correspond to the LOW state.

“Source current of IOH” is redundant phrasing; the standard symbol alone is correct.

Common Pitfalls:

Confusing IOH and IOL; assuming symmetric sourcing and sinking abilities; overlooking worst-case values for fan-out calculations.

Final Answer:

IOH