The operational 714 (not the 741) is an old Raytheon type that is no longer common today. The circuit can be implemented with modern operational. The power supply must be symmetrical.
In the figure we have a simple way to produce tone in a piezoelectric transducer. The frequency depends...
This absolute value amplifier was found in a 90's EDN. Equivalent amplifiers can be used. The...
The integrated circuit used in this configuration for noise reduction on FM radios is not common...