| （英） |
An inexpensive non-metal-contact voltage measurement has been attracting much attention, since voltage of a commercial power supply can be measured safely and conveniently. Therefore, some methods of measuring voltage from outside of an electric cable were presented and applied. However, almost of the all proposed methods require grounding, which means at least two probes are needed and application is difficult. In this study, we measured an electric field, which proportion to the voltage, emitted from the cable by a single probe. We used a piezoelectric film which has an electrode pair that sandwiches a dielectric to receive the electric field. The piezoelectric film placed over the electric cable and received the electric field that correlated to the voltage of the cable. The received electric field were converted to a potential difference between the electrode pair of the piezoelectric film. The measured waveform showed a high correlation coefficient of 0.99 with the voltage waveform applied to the cable, although there was a phase difference. The fabricated sensor had high linearity for electric field and stable frequency characteristics from 25 Hz to 1 MHz. The proposed measurement method is expected to be realize inexpensive and safe measurement devices that do not invade electric facilities. |