This circuit was found in a Popular Electronics from the 90's. The transistors are general-purpose types and the loaded load depends on the voltage and must have a maximum current of 100 mA.
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...