SWITCHED CAPACITOR TYPE HIGH-SENSITIVITY SENSOR CIRCUIT AND PINBALL PASSAGE DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a sensor circuit which detects fine capacity variation that a fine-capacity capacitor has depending upon a physical phenomenon to be detected with very high sensitivity and a high-performance pinball passage detector that the sensor circuit is applied to. SOLUTION: The sensor circuit detects the fine capacity variation that the fine-capacity capacitor Cs has according to the physical phenomenon to be detected with very high sensitivity and is so constituted so that a period wherein a voltage source -Vr is connected to the Cs to quickly charge the Cs with a constant voltage and a period wherein an integrating circuit is connected to the Cs to discharge the Cs and accumulate electric charges are repeated by a switching circuit 1 driven with a specific high-frequency switching signal; and the capacity variation of the Cs is detected as output voltage variation of the integrating circuit.