This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The circuit does not need power, as it is powered by the line call signal itself.
We found this sensitive moisture detector in an old documentation. The circuit uses a common JFET,...
This simple 2-transistor radio is from Radio Electronics in October 1952. The circuit outputs a...
This circuit was obtained in an American documentation of 1964. The transistors are of the time....