Definition of electric current for circuit analysis In electrical engineering, current is most generally defined as the movement of what quantity?

Introduction / Context:
Current appears in Ohm’s law, Kirchhoff’s laws, and Maxwell’s equations. A precise definition prevents confusion across different media where charge carriers can be electrons, ions, or even “holes” in semiconductors.

Given Data / Assumptions:

• No specific medium is stated (metals, electrolytes, plasmas, semiconductors are all possible).
• We need the most general, medium-independent definition.

Concept / Approach:
Electric current I is the rate of flow of electric charge Q through a surface: I = dQ/dt. In metals, charge transport is mainly by electrons; in electrolytes, by positive and negative ions; in semiconductors, by electrons and holes. Thus “charge” is the correct universal description, not a specific particle type.

Step-by-Step Solution:

Verification / Alternative check:
Device physics texts consistently define current density J = ρ_v * v for moving charge density ρ_v, reinforcing “charge” as the general concept.

Why Other Options Are Wrong:

• Electrons: correct in metals but not universal.
• Protons/nuclei: do not move in metal lattices; ionic currents may include cations but that is not universal.

Common Pitfalls:
Equating “current” only with electron drift from DC wire examples; broader contexts exist (electrochemistry, plasmas, semiconductors).

Final Answer:
Charge