This circuit is for old telephones with analog lines. It was found in the May 1988 Radio Electronics magazine. The circuit is powered by the line signal voltaje.
This circuit is from a 1968 publication. It uses germanium transistors from the time, having...
This circuit can be used as shield or to drive powerful loads from low current switches such as...
This is a 6-transistor transistor receiver manufactured in the 60s. The circuit is a...