Various A/V devices, including a big TV and two computers.
This shows a 19 millisecond sample from about a minute ago. Since US mains runs at 60Hz, 19 msec is just over one full cycle, which you can see here.
Microwave, toaster oven, etc.
This shows a 19 millisecond sample from about a minute ago. Since US mains runs at 60Hz, 19 msec is just over one full cycle, which you can see here.