The SillOO series circuit input is connected to a capacitive field sensor-possibly a piece of doublesided circuit board. Any induced voltage change on the plate is fed to the input of the peak detector section of the op-amp circuit. The Schmitt trigger monitors the voltage across the capacitor and changes its output state when the capacitor voltage crossed the 2.5-trigger point.
The output from the Schmitt trigger switches between 0 and 5 V and is microprocessor compatible for sensor applications. such as computercontrolled intruder alarms.