Using a standard multimeter, this circuit from a 73 magazine for radio amateurs provides an output proportional to the inductance under test. The circuit is TTL and must be powered with 5 V.
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...