An instrument for the measurement of large alternating currents

An arrangement of the measurement and oscillographic recording of large alternating currents, consisting of a special air-core transformer and an amplifier, is described. The air-core transformer is wound on a flexible core of small cross section, permitting its easy linkage with the current to be measured without disturbing the circuit. The underlying theory of the air-core transformer is discussed, and the modifications necessary to make it suitable for measurement purposes are described.