We found this circuit in an old documentation, but the components used offer no difficulty in obtaining it. The CMOS integrated circuits are powered by a 6V supply.
We found this circuit in an American 80's documentation. The circuit can be adapted to function as a...
This 80's circuit, suggested in Texas Insrtruments documentation, uses a Hall effect sensor. The...
This interesting benchtop circuit was found in the May 1977 issue of Radio Electronics magazine. The...