This configuration can be found in several articles on this site. The one shown in the diagram is from the datasheet of the LM101 series amplifiers, but it can be implemented with other types.
This circuit was obtained from an American publication of 1982, but can be easily assembled today...
This switch circuit for an incandescent lamp can have its duty cycle programmed by the...
This circuit with the LM339 voltage comparator was found in an American documentation from 1991....