We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the time and the diodes in the dotted board must be mounted on the output transistor heatsinks.
This circuit was found in a 1995 documentation. It drives a set of sequential LEDs from the sound...
This circuit was found in a 1968’s publication and uses germanium transistors. Equivalents can be...
The integrated circuit used is equivalent to the 555 and the transistor can be the BC558. R1 and...