We find this circuit in an old documentation, but it can be made using modern transistors. The circuit trips, producing a continuous sound when the sensor is wet. The 1 mOhm resistor is actually 1 Mohm.
This circuit was obtained from Popular Electronics from March 1967. The transistor used is from...
The purpose of this circuit is to control the high and low light of a car, detecting when a...
This circuit triggers three incandescent light bulbs following the audio signal applied to its...