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 the Radio Electronics magazine of April 1991. The circuit is based...
This experimental good sensibility radio was obtained from a 1968 magazine. The magazine no longer...
s. In it, a set of batteries or battery provides the reference voltage for the output. The...