Dirty-electricity (line harmonics) meter
Plugs into a socket and reports high-frequency harmonic content riding on the mains, the quantity used to judge dimmers, LED drivers, inverters and switch-mode supplies.
conducted harmonics, roughly 2 kHz – 1 MHz
Last verified 12 August 2026.
Also searched as: Graham-Stetzer meter, line noise meter, microsurge meter
- Band covered
- conducted harmonics, roughly 2 kHz – 1 MHz
- Quantities measured
- electric field strength
- Typical price
- $80–$400
Detects
- Harmonic content injected by phase-cutting dimmers and cheap switch-mode supplies
- Relative before/after effect of removing a suspected device
- Power-line-communication carriers used by some solar optimisers and smart appliances
Cannot detect
- Radiated fields — this is a conducted measurement at the socket
- Which device is responsible, without switching devices off one at a time
- Anything expressible in a recognised SI exposure unit: the common 'GS units' scale is proprietary and not an exposure metric
What to insist on
- A stated frequency window rather than an arbitrary index
- Readout that can be compared over time and between circuits
- Ideally an oscilloscope line adapter for anyone who needs the actual waveform
Related records
- Dimmer switch and phase-cutting controls
Phase-cutting dimmers chop the mains waveform and inject harmonics from a few kilohertz up to about 1 MHz onto the building wiring — the classic source of what practitioners call dirty electricity.
Sources & emitters
- LED lamps and low-cost drivers
The switch-mode driver inside a cheap LED lamp can put measurable high-frequency harmonics on the circuit and produce visible flicker; well-filtered drivers do neither.
Sources & emitters
Sources
- sbm-2024 Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024) — Institut für Baubiologie + Nachhaltigkeit (IBN), 2024. ngo, link checked 2026-08-12.
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