This circuit was obtained in a Motorola documentation from 1968. The circuit uses a power transistor of the time. Modern equivalents according to the load current and voltage can be used.
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...