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.
Found in 90s Radio Electronics, this shield can control high voltage loads in the power grid....
This interesting 80's logic circuit consists of a gate that can be programmed according to the...
In this circuit of an American documentation of the 90s, when the light is cut, we have the...