This 80's documentation circuit includes an amplifier of the era. Used integrated circuits are uncommon today but can be used equivalents.
This two-channel bargraph meter uses a single KAA2281 integrated circuit. Found in the January 1991...
This 80's circuit, suggested in Texas Insrtruments documentation, uses a Hall effect sensor. The...
A negative pulse applied to the input of the circuit shown in figure bellow turns on the relay....