Found in a documentation from the 90s, this circuit limits and amplifies a voice signal in the 800 to 3000 Hz range and is intended for transmission systems.
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...