This circuit was found in a 1964 Electronic Design. The components are of the time, and modern equivalents can be used. Note the multi-emitter transistor.
May 2016 - Mouser Electronics is sourcing the new high-performance audio amplifiers with bipolar...
Using this circuit a low current switch can be used in the control of heavy duty loads, powered...
This timer with 1 second accuracy was obtained in a 1973 documentation. The Buzzer is a low-power type...