This circuit was found in a 1965 General Electric manual. What it does is give a warning if you leave the vehicle with the headlights on or lights inside.
This circuit is used in transceivers, enabling input selection by diode switching through polarity...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...
This circuit was found in an Italian magazine Elettronica Prática of 1977. The transistors can be...