You’re right we don’t know for sure. What we do know is the types of components used in today’s electronics are generally much more sensitive than the electronics used in the 50s when EMP effects were observed from the nuke testing.
“What we do know is the types of components used in today’s electronics are generally much more sensitive than the electronics used in the 50s when EMP effects were observed from the nuke testing.”
We also know that portable devices, for instance, have very little area to absorb energy. So a great many of the devices - because of design practices and other things will have a statistically significant survival rate. We just don’t know what it is.