A method for non-contact measurement of a dimension and/or an electrical
property in an electrically conducting object to be measured by using
electromagnetic induction. An electromagnetic field is brought to
penetrate through the object to be measured. A transmitter coil is place
on one side of the object to be measured. A receiver coil is placed on
the other side of the object to be measured. A magnetic field is
generated in the transmitter coil. A sudden change is generated in the
magnetic field generated in the transmitter coil from one level to
another. The voltage induced in the receiver coil is detected. The period
of time that elapses from the time of the change of the magnetic field in
the transmitter coil up to the time when a voltage starts to be induced
in the receiver coil is determined. The magnitude of the induced voltage
is determined. The thickness and/or electrical conductivity of the object
to be measured is calculated.