This circuit has a sensitivity of 2uW. We found it in documentation from the 1980s. The integrated circuit is from that time. Equivalents can be tried.
The resistors R determine the frequencies of the oscillator together with C. The circuit is from a...
This circuit can be used as shield or to drive powerful loads from low current switches such as...
Two of the four gates of a 4011 is used in this biestable touch circuit. Do not use a power source...