| 摘要 |
PURPOSE:To accurately test a filter with an inexpensive device by charging an LC filter terminal to be tested by a DC power source, shortcircuiting to discharge it, and analyzing the discharging current characteristic by the amplitude attenuating characteristic of the discharging current and an intrinsic vibration frequency. CONSTITUTION:A filter tester connects a capacitor 31 for absorbing harmonic wave resonating in series with a reactor 32, and provides a power source 1 for discharging the capacitor 31 at both ends of the capacitor 31. A test main circuit 41 for shortcircuiting the series circuit is formed of a switch 2, the discharging current of the main circuit 41 is detected by a current detector 4, and input to a discharging current characteristic analyzer 5. The sanalyzer 5 is composed of a Q counter 56, omega0 counter 54, and counts the discharging current through a full-wave rectifier 51 and a current/voltage converter 52 by a level detector 55 at the output signal number of the predetermined level or higher by the counter 56. The frequency is measured by the counter 54 through a synchronization detector 53 to confirm the characteristics. |
