This circuit was found in a 1985 documentation. It provides an audiovisual indication of the presence of moisture or water in the sensor. The circuit can be powered by voltages from 6 to 9 V.
We found this circuit in a 70s Electronic Design documentation. The circuit uses general-purpose...
Texas Instruments ESD122 Electrostatic Discharge Diodes (ESD) can be ordered from Mouser...
This circuit is suggested by Motorola as the basis for the MC3324 A integrated circuit and has a...