This circuit was found in an Australian publication from 1991. It is a transmitter that transmits a signal when it detects moisture. The range is on the order of a few tens of meters.
In the figure we have a circuit with two operational amplifiers 741 capable of doubling the...
What differentiates this circuit from the previous one is the need for a much smaller current to...
This circuit was obtained in a Maxim documentation from the 90's. The circuit applies to...