# Duty cycle

> The fraction of time a transmitter is actually radiating — the reason a peak reading and a time-averaged exposure can differ by a factor of a hundred or more.

- Canonical URL: https://emfbase.com/glossary/duty-cycle
- Collection: Glossary
- Record id: `glossary:duty-cycle`
- Status: verified
- Last verified: 2026-08-12
- JSON: https://emfbase.com/api/glossary/duty-cycle

## Key values

- **Category:** measurement

## Definition

Most digital transmitters send bursts rather than a continuous carrier. A smart meter may transmit for well under one percent of the time, so its peak burst amplitude says little about exposure as regulatory limits define it, which is averaged over 6 or 30 minutes. Any comparison of a measurement to a limit is invalid unless both refer to the same averaging.

## Sources

- `fcc-1310` U.S. Government Publishing Office (eCFR). *47 CFR § 1.1310 — Radiofrequency radiation exposure limits*. https://www.ecfr.gov/current/title-47/section-1.1310 — regulation, link checked 2026-08-12
- `sbm-2024` Institut für Baubiologie + Nachhaltigkeit (IBN) (2024). *Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024)*. https://buildingbiology.com/site/downloads/SBM-2024_EVALUATION_GUIDELINES_EN.pdf — ngo, link checked 2026-08-12

Data licence: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Dataset version 2026.08.1. Retrieved from EMFBase, https://emfbase.com.

This record is reference data, not medical or legal advice. Regulatory limits, scientific guidelines and precautionary values are labelled separately and answer different questions.