[cctalk] Re: EMP was: oscilloscopes

Well, if you're after an EMP-tolerant oscilloscope, there's always the mirror-galvanometer + rotating mirror variety. Precedes the development of the CRT by quite a bit. Runs fine with clockwork. It's amazing what can be done with simple electrics and mechanics. Anyone remember using the wall-galvanometer + telescope setup in physics classes? Or am I dating myself again? I recall working on L&N clamp-galvanometer chart recorders with clockwork drive and a single dry cell to provide power to a wheatstone bridge. L&N "Micromax". The idea is to sense the position of the galvo needle (periodically clamped) and adjust the setting of the slidewire to bring things into balance, which drives the recording pen. They were still in use in steel mills when I was in my salad days. The electronic versions with chopper amplifiers and regular servo drives were known as "Speedomax" Probably not EMP-safe. --Chuck