This circuit uses a high brightness LED to simulate a LASER. We found it in a 1991s PE Hobbyst Handbook. The components used are all common.
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...