We found this circuit in a 1964 Electronic Design. The components are from that time, but the circuit can be made with modern equivalent components.
This circuit, found in an American publication from the 1970s, produces an audible tone in a...
This circuit was found in a 2006 publication. It can serve as the basis for a microcontrolled...
By adding a transistor to the output and some polarization features we can obtain a higher output...