Disclosed is an electromagnetic-force-balancing-type electronic balance
having a magnetic circuit which includes a yoke 4, a first permanent
magnet 1, a pole piece 3, a second permanent magnet 2 and a cover 5. A
connection member 7 made of a magnetic material is disposed in an air-gap
region included in the magnetic circuit. The connection member 7 may be
disposed between the second permanent magnet 2 and the cover 5 or between
the cover 5 and the yoke 4 to facilitate assembling operations.
Alternatively, first and second gap-defining members 8, 9 made of a
non-magnetic material may be disposed, respectively, between the first
permanent magnet 1 and the yoke 4 and between the second permanent magnet
2 and the cover 5, to provide symmetric properties in magnetic
sub-circuits so as to counteract an imbalance in hysteresis
characteristic. The present invention can suppress adverse influences of
a magnetic resistance caused by an air gap existing in the magnetic
circuit of the electronic balance.