| 摘要 |
PURPOSE:To detect deterioration in a capacitor at an initial stage where no remarkable change in characteristics is observed by adding a constant current waveform signal such as a rectangular wave to integrate a response signal due to voltage drop and detecting the change in characteristics based on the integrated value. CONSTITUTION:A rectangular wave signal at low frequency, for example 1kHz, is supplied from a measurement signal source 10 to an electric double layer capacitor C1. After the signal through the capacitor 1 is A/D-converted 11, it is acquired into a CPU 12 and a phase is detected. Then a latter half of a response signal is integrated 14. The response signal appears as a rectangular wave approximate to the measurement wave when the capacitor C1 is normal, while not only the waveform itself but also its position largely varies when deterioration develops. When the deterioration is detected, a measurement signal is added to a normal capacitor C1 to make reference data, and an increase by 5% for example of the reference data is set as an upper threshold. Then the response signal of the capacitor C1 to be measured is monitored by the CPU 12, and when the upper threshold is exceeded, the deterioration is determined and displayed 15. Thus early and correct detection for the deterioration is possible. |
