What electronics is worth protecting?

[NorthernSanctuary]

With respect to putting electronics in the microwave, there is a good risk it won't work. The perforated metal screen is designed to block the microwave effectively, but it will not block energy of a higher frequency (the size of the hole affected what will get blocked, or not blocked). An EMP has a very short duration, and if you look at the generated frequencies, it has a very wide spectrum, so the higher frequencies will get through.