Found in Popular Electronics from the 90s, this 1.5 A power supply can supply voltages selected by a switch. The splitter resistors determine the output steps.
This simple alarm circuit was found in a 1998 documentation. When the sensors are activated, the...
This circuit was found in an old American documentation. The integrated circuit used is uncommon...
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...