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.
This circuit was found in the April 1971 Radio Electronics magazine. It uses common transistors and can...
This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963....
Using a 4017 as a base, this circuit from a 1990s Popular Electronics generates low-frequency...