3 ms·Power supply and common mode noise can be 60 Hz.by kazinator 2y agoPower supply and common mode noise can be 60 Hz.kragen 2y agoAnd its harmonics, if you're standing near a fluorescent lamp.kazinator 2y agoYes, but I'm trying to argue that the frequency can go at least as low as 60.kragen 2y agoSure, or 50 most places. Notching that out is often worthwhile.