Are you aware of similar contraptions being used in the real world, like EMP devices?
It might have been the Shawn Ryan one where the guy also talked about using nets he requisitioned from German forces that the US didn't have. The same type Japanese police used for years to catch bikers IIRC.
Slight chance it was a book though, as I was doing research on a different, specific topic at the time.
Some comes up on YT too: https://www.youtube.com/watch?v=cuus8OtPY0w
There were some studies done about using low-power nukes to EMP things without causing significant damage.
I don't think it has been done.