This circuit was found in American documentation from the 90's. The transformer determines the output voltage. The transistor must be equipped with a heat sink.
The figure shows how to implement an R-S flip-flop or bistable reset-Set with an LM3900...
This circuit was found in the SGS manual of linear integrated circuits of 1982. The CMRR depends on...
This simple circuit with transistors turns on a small lamp when it gets dark. The sensor is an LDR...