This 1967 commercial radio covers 6 wave bands selected by appropriate coils. The circuit currently uses critical components, such as coils and transformers.
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
This interesting FET-tester circuit was obtained from an old American documentation. The bipolar...
This old VHF TV booster that also serves FM was found in Radio Electronics magazine from April...