Amp Nerd

A steady meter reading near 120V does not prove that the supply is free from power-quality problems.

A balanced three-phase supply has three waveforms separated by one third of a cycle, or 120 electrical degrees.

A large load can pull the local voltage down briefly when it starts because the supply path has impedance.

A generator can remain below its watt rating while delivering an unsuitable frequency or a poor response to a sudden load.

An ordinary transformer transfers energy through changing magnetic flux.

High transmission voltage helps move a given amount of power with less current.

Harmonics describe frequency components in a repeating electrical waveform, not just musical overtones.

A blackout removes the supply, while a brownout leaves it present at reduced voltage.

Voltage describes an electrical potential difference; frequency describes how often an AC waveform repeats.

Your home receives AC partly because changing voltage with transformers made large electricity networks practical.