Found in Unitrode documentation from the 1980s, this circuit makes use of PUTs, currently common components. The circuit must be powered with voltages around 15 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...