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 is an application circuit of the Texas Instruments (2019) component datasheet itself. The...
This conventional 12 V power supply stabilized with 2 A current was found in a 1995 documentation. Its...
This simple oscillator with two general-purpose transistors has its frequency given by capacitor...