We found this circuit in an American documentation from the 80s. The integrated circuits are operational amplifiers of the time. We can test modern comparators like the LM339.
This circuit was obtained in a 1978 English magazine. This adjustable stabilized power source...
This circuit was found in old documentation, but as it uses the 555 it can still be easily...
This timer with field effect transistors was obtained from Fairchild documentation. The times...