This circuit from a Popular Electronics from the 90s uses a common optocoupler and a general-purpose transistor to control a sensitive relay that can be from 6 to 12 V.
This circuit is more sensitive than the previous one, in the sense that we can use weaker and more...
This 3-transistor timer was found in the January 1994 issue of Electronics Now magazine. The...
This circuit appears in other articles in this section, but it is very interesting. It is a...