It serves as a reference, since today we can have simpler and more compact solutions. This circuit is from an Electronics Experimenter Handbook from 1992. The integrated circuits are from that time.
This low current parallel or shunt type regulator was found in documentation from the 60's. The...
This circuit is found in a 1975s documentation for radio amateurs. It was developed to recognize a...
The displayed relay operates with an audio signal applied to the input. The transistors can be...