Electricity & circuitsSchool & A-level
Alternating current
Current that changes direction periodically, commonly with a sinusoidal waveform.
Notes & references
The quoted mains voltage is an rms value, not its peak voltage.
Also known as: AC · a.c.
Data
School, undergraduate & advanced physics
Direct reference
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Dictionary
1 entry in Dictionary. Search: all. Topic: all. Level: all. Letter: all. Titles first, then explanatory matches.
Coverage, notation & sources
A growing reference from school fundamentals through undergraduate and selected advanced physics. No finite collection contains every specialised equation or theory; use topic and level filters, and always check assumptions.
Definitions use original wording, and each reference links to source material. Study labels are guides, not exam-board checklists. Worked check questions are educational examples, not an exam question bank.
Equations use SI quantities unless stated otherwise. Numerical values retain the units, precision and conditions of their source. Diagrams are explanatory models; their captions identify simplifications.