This circuit was obtained in a 1980s publication, but it can be easily assembled today, as all components are common. The transformer is 12 + 12 V with at least 1 A and the diodes 1N4002.
This circuit is from the 1982 SGS linear integrated circuit manual. The LS141 is like to the 741...
The integrated PLL XFl2211 (Exxar) is used to decode data transmitted by tones R1, C1, C2 and C3...
This bistable touch sensor circuit uses a relay and is very sensitive. We found it in a 1990...