This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit equivalent and the relay is of the sensitive type for low voltage, according to the power supply.
This pulse width modulator is from the SGS Integrated Circuits Manual 1982, the operational can be...
We found this circuit in a publication from the 1970s. The circuit detects when the pulse duration is...
This circuit using current components was found in an old documentation. It is a sequential circuit...