Homer J Simpson wrote:
"Jeff Wisnia" <jwisnia@xxxxxxxxxxxxxx> wrote in message
news:zLydnZVzrJEpLYfYnZ2dnUVZ_tWdnZ2d@xxxxxxxxxxxxxxxxx
I believe the ammmeter is what I used to know as a "moving iron"
type, and IIRC the restoring force was supplied by some kind of
permanant magnet field, not by a mechanical spring. Am I right about
that?
Nope. Still a spring.
http://www.tpub.com/content/doe/h1011v4/css/h1011v4_76.htm
Moving iron vane - The moving iron vane meter operates on
the principle of magnetic repulsion between like poles. The
measured current flows through a field coil which induces a like
magnetic field into a fixed and moving vane causing the moving
vane to deflect a pointer in proportion to the current or
voltage applied to the coil.
I hear what you say about a spring, and it makes sense that there may be
one there. But it's interesting that the reference link you gave
mentioned "springs" when describing the first two meter types, but not
the moving iron one. Wonder why? Probably just an oversight.
Jeff (Who is NOT going to tear that old meter on the Eico 1050 apart to
find out.)