Mains frequency in Hertz (Hz). Attention: The flicker frequency of the light source is twice the mains frequency!
If you measure the light frequency with an optical frequency meter, you have to divide the light frequency in half to get the mains frequency. This particularly applies to lights, which generate their own frequency independent of the mains frequency, as, for example dimmed LED lights.
| mains | lights | |
|---|---|---|
| National grid Europe | 50 Hz | 100 Hz |
| National grid USA | 60 Hz | 120 Hz |
| LED Dimmers | 30-200 Hz | 60-400 Hz |