  This is the problem of the 7-th international Experimental Physics Olympiad
"The Day of the Inductance". A large inductance made by a general impedance
converter is measured by the Maxwell-Wien bridge. The youngest students (S
category) have the problem to measure the parameters of the elements in the
experimental set-up. The students at middle age (category M) should balance a
Wheatstone bridge with resistors only. The inductance measurement is supposed
to be accomplished by the students from the upper age (L category) only. From
the university students (XL category) we expect error estimation and
professionally made measurement protocol. As a homework problem (Sommerfeld
price) the general formula for the impedance of the general impedance
converter, where the general equation for operational amplifiers is included,
has to be derived. Problems for further work are also given in the text. The
described set-up can be considered as a prototype for companies producing
laboratory equipment.
