This circuit is from Mullard 1969 documentation. The circuit operates at a relatively high supply voltage and has a 10 Vpp output. The transistors are of the time, but admit equivalents.
This circuit can be used as a buzzer from 3 different locations, allowing you to identify where it went...
We found this circuit in an Electronic Engineering of the 90s. The circuit can be implemented with any...
This adjustable source was found in a 1979 documentation, but all components are still common...