We found this circuit in a Poptronics from the 90's. Equivalent operational amplifiers can be used. The circuit must be supplied by a symmetrical source.
This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic...
Found in a 1966 American publication, this circuit generates a 25 MHz rectangular signal for...
This conventional 12 V power supply stabilized with 2 A current was found in a 1995 documentation. Its...