Found in a 1990 PE Hobbyst, this 4-digit circuit has a high response speed. The circuit is based on TTL logic.
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...