This basic relay configuration was found in a July 1994 Electronics Now. The relay is supposed to be sensitive, and the times are changed by changing C1.
We found this automotive application circuit in an old American documentation. All components are...
This filter has a cut-off frequency of 1 kHz by letting pass those that are above this value. The...
This circuit was found in a 1967 US documentation. It shows how to build a gain control by digital...