THey were developed for war time bombs in the mid 60's. e-cells iirc.
I got some early data sheets as I did some consulting with consults.
(A strain gauge for Helicopters keeping from picking up to heavy a
load.)
[ that was a physics nightmare - twisting, bouncing load that might be
to much of a load or just enough.]

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder