We found this circuit that converts a direct voltage into a proportional frequency signal. The circuit is from an Electronics Now from April 1993. The JFET can be of any type.
We found this circuit in an old publication from Argentina. The relay must be of the sensitive type,...
This circuit can be used with TTL or CMOS circuits with slightly higher voltage supply. The...
We found this timer circuit in a publication in the 90's to turn off a device powered by 4...