This circuit interrupts the power supply when grounding is missing. The circuit is from an old documentation (from the 80's) using current transformers and other components of the time.
This UPS circuit was published in the March 1985 issue of Radio Electronics magazine. The...
This simple tone control using two transistors was found in an Electronics Today International of the 90s....
An excellent signal generator for the audio track was found in a 1983 documentation. Its complete...