“Is it possible that the fast switching (sharp edges) occurring in digital circuits could emit spikes of ionizing radiation?”
No. There are strict laws against EMI—ElectroMagnetic Interference. UL and other independent test labs verify. Often the tiny writing on labels of electronic equipment say they comply with FCC rule xxx. That encompases it.
“Is it possible that the producer of microwaves in a microwave oven produces ionizing-frequency spikes”
It might inside, but not outside. They are faraday caged against EM leakqge, and also tested for compliance.
You have very good electronic knowledge re leading edge spikes, btw. Intereresting topic. Sharp transitions in a voltage/current waves send harmonics screaming out. The sharper the edge, the higher amplitude the harmonics. They come across the radio as that noise...ultimate is spark gap generator. They drown out everything. If you use an antenna as 1 part of it, you would knock signals out all over the place. Illegal as hell, just sayin...lol.
“No. There are strict laws against EMI”
Ok. The circuits are shielded. But can the circuits themselves generate edges sharp enough to emit ionizing radiation.
Regarding 5g, it doesn’t use frequency bands that aren’t in use now. Correct? I think the only new things in 5g are maybe a different modulation scheme and a larger number of smaller cells. Maybe it’s also made possible because better handset electronics are now available at consumer prices.