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 configuration was found in an American publication from the 90s. Operators admit equivalents just...
The circuit shown in the figure has basically the same configuration as any TTL oscillator, with...
This circuit with the PLL567 serves as a decoder for PWM modulated signals of frequencies up to...