Found in a Popular Electronics from the 90s, this circuit makes use of an unusual integrated today. The coils are for the medium wave range.
This lie detector was obtained in a Japanese publication in 1967. The component with a different symbol...
This old amplifier uses germanium transistors from the time. The circuit is from a Mullard...
This circuit is from an American publication from the 60's. The transistors are made of germanium. It...