We found this precision circuit in a manual from the 80's. The operational amplifier is of a common type at the time, and equivalents can be tested. Transistors are general purpose types.
This circuit was found in an American 1960s documentation. The circuit uses transistors of the...
This alarm with sensors in series and parallel was found in the 1995 Encyclopedia of Electronic...
This non-inverting comparator was found in old American documentation. Formulas next to the...