In fact, this 1967 Electronic Design circuit generates two symmetrical ramps whose frequency depends on the values of the components used. Modern equivalent transistors can be used.
This circuit provides just over ½ W to a small speaker. We found this configuration in an old...
Found in American documentation from the 1980s, this circuit can be designed with equivalent...
This circuit was found in the December 1993 issue of Electronics Now. With the components shown the...