This circuit, published in the 1980s, can be applied to operational amplifiers of almost any type. The power supply must be symmetrical.
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...
Found in documentation from the 1990s, this circuit supports equivalent transistors. The range is on...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...