I've heard that if an EMP weapon were used, *nothing* in the blast area
that relies on electricity would work.
Is this really true?
If you had an alkaline battery, it would still put out a voltage,
correct?
Failing that, one could still take a roll of paper towels, immerse the
towels in a salt solution (table salt should do), place alternating
plates of copper and zinc (or any two dissimilar metals), and obtain a
current... right?
Would motors still work, or would their windings be guaranteed
destroyed in an EMP blast?
Thanks,
Michael
As you suspect, the statement that after a detonation of an "EMP
weapon", "nothing with 2 asterisks" in the "blast area" that "relies"
on electricity would work is a bit inaccurate and/or misleading. Much
electrical and electronic equipment already in existence would be
destroyed or damaged. Some would not. This undamaged equipment would
work fine after the pulse had gone by. Yes of course an alkaline
battery would still put out a voltage. If it was in a circuit it might
have got fried first. Of course if you made a voltaic pile out of wet
tissues and dissimilar metals it would work. An EMP device does not
abolish electric currents for ever within the blast area.
If by an "EMP weapon", you mean a nuclear device optimized for EMP (all
nuclear weapons produce EMP to some extent), they work by sending out
an electromagnetic pulse which would induce more or less heavy currents
in conductors. This could damage electronic equipment and electric
power lines, generating stations and substations.
The resistance to EMP by device is listed below, from most to least
vulnerable:
1. Integrated circuits (ICs), CPUs, silicon chips
2. Transistors
3. Vacuum Tubes (also known as thermionic valves)
4. Inductors, motors
Transistor technology is likely to fail and old vacuum equipment
survive. However it must be considered, that different types of
transistors and ICs show different sensitivity to EM: bipolar ICs and
transistors are much less sensitive than FETs and especially MOSFETs.
To protect sensitive electronics, a Faraday cage must be produced
around the item. This can be done by wrapping the item, such as a radio
in foil (any external connections should not touch foil) without any
holes. This will shield the item from EM fields.
So you can see that motors are fairly low down the list of vulnerable
equipment.
A strike *guaranteed* to burn out the windings in an electric motor
would most likely destroy the building it is housed in by blast or heat
anyway.
When a defecting (for money) Soviet pilot landed a MiG fighter in japan
towards the end of the Cold war, and US techs stripped it down, they
laughed at how "backward" the Soviets were, still using vacuum tubes in
the 1980s. Such dinky little tubes as well. Then they stopped laughing
when they noticed a couple more features and realised they were looking
at a practically EMP proof plane.