This resistive sensor was found in a 1969 US documentation. The circuit uses transistors of the time, but current equivalents can be employed.
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...