This rain, flood or leak sensor was found in a 90s Popular Electronics. All the components used are common today. The transistor can be the BC548.
In the figure we have an audio amplifier suitable for portable applications in both mono and...
This circuit was sent by our longtime collaborator, Adriano Muniz Moura – Pirapora-MG. The...
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...