BASIC NEC 2023

AC Fundamentals Practice Test

Free online AC (alternating current) fundamentals practice test. 25 basic electrical questions on sine waves, frequency, RMS and peak voltage, phase, and how AC power is generated. Good for electrician exam prep.

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AC (alternating current) is the type of power delivered to almost every home and business in the United States, standardized at 60 Hz and 120/240 volts. Unlike DC, AC current reverses direction many times per second, tracing out a sine wave. Know the difference between peak value (the highest point of the wave) and RMS value (the "effective" value that behaves like an equivalent DC voltage for heating purposes) — when someone says "120 volts," they mean RMS. Also get comfortable with frequency (cycles per second, in Hz) and phase (timing between two waveforms).

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BASIC · NEC 2023
AC Fundamentals Practice Test
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EXAM CARD BASIC
Questions0
Time limit38 min
Pass score75%
Code editionNEC 2023
DifficultyIntermediate
Last reviewedJun 2026

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Source: NEC 2026 (NFPA 70)