XCII. On the measurement of the natural frequency of an inductance coil at audio-frequency
Heiichi NUKIYAMA, Koichiro KOBAYASHI · The London Edinburgh and Dublin Philosophical Magazine and Journal of Science · 1924
We measure the frequency of the alternating current by the known mutual inductance and capacity with Campbell's frequency bridge. The same circuit can be utilized to determine the natural frequency of a coil used as the primary of the mutual inductance, if we know the frequency of the current and the capacity which gives the balance. In the experiment described in this paper the frequency is determined by standard tuning-forks. A theory by which the natural frequency and the self-capacity of the primary coil can be obtained by taking balance at two known frequencies is worked out. The actual method of experiment and the experimental check of this theory are also described. When the sharpness of the balance is greatly affected by the presence of the self-capacity, it can be improved by a simple modification of the circuit as shown in fig. 6.