In the figure we have the typical circuit of a stereo decoder using the TBA450N integrated circuit. The circuit is from the 1976 Siemens manual. No information was given on the coils.
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This power source with silicon diodes at a time when valves were still used was found in Radio...