Inductive position sensors and circuit configurations are disclosed for
the measurement of linear, rotary, or curved position along a motion
axis. The simplified sensor structures combine one or two parts of a
movable core element with a simple planar substrate having first and
second inductances connected in series. Movement of the core element in
parallel to the planar substrate causing the impedance of at least one of
the inductances to change. Simple circuit configurations are taught by
which the impedance change is converted into a useful output signal that
indicates position along the motion axis.