This circuit is from 1999 documentation. However, it can still be easily assembled, as all components used are common. The sensors can have their quantity increased, being connected in parallel.
This is another practical idea found in a 1997 documentation. This circuit allows a DJ to change the...
Found in a 90s Popular Electronics, this circuit can power a miniature railroad with voltages of 15...
Based on the frequency of the power grid, this circuit produces square signals for use in digital...