抄録
A method was devised whereby dielectric constant of a microamount of substances could be measured with simplicity, high sensitivity, and in a high degree of stability by an operation designed to bring the Lissajou's figure of the brawn tube to a straight line. One of the principles of this method lies in the fact that the phase difference in the circuit is compensated by the fine adjustment of the variable condenser inserted in parallel with the sample and to catch this at the moment at which the Lissajou's figure changes from ellipse to a straight line. The sensitivity at the time of measurement is especially extremely high since this moment is selected so that the pair of parallel resonance circuits is in perfect resonance. Another is the fact that the variation in the voltage of electric source changes only the length and brightness of the Lissajou's figure and the moment that the figure itself changes is only when oscillating frequency changes. Moreover, there is no objection, theoretically, of fixing the oscillating frequency and therefore, crystal oscillator is used in this devise. Therefore, stability is good, voltage stabilizer is not required, and there is no variation even if the period of determination extends over 20 to 30 hours, Since this method possesses high sensitivity and high stability, the amount of the sample required is very small, only 0.5-10cc. of a solution or 1-10mg. of a compound for the measurement of dipole moment will suffice. Further, since the measurement is made by visual observation, operation is very simple and sensitivity is good, and the apparatus can be constructed at a comparatively low cost because the circuit is comparatively simple.
