The Kohlrausch ammeter is based on the measurement of the force acting between a solenoid and a soft iron rod inserted inside it. In this article, we present a new version of the instrument for educational purposes: in our device the dynamometer, which is usually employed to measure the force, is replaced by an electronic balance. The operation of the instrument is satisfactory: the precision is better than 1%. Furthermore, the measurements can be useful to improve students' knowledge of magnetism and magnetic materials. (Contains 5 figures, 4 footnotes, and 1 table.)