This circuit is from the time when cars used contact breakers. This 80's version measures the dwell angle of the contact breaker for dwell adjustment using an era integrated circuit, the LM3917.
We find this circuit in a 1987 publication. It makes use of comparators constructed around the 741...
We found this circuit that warns when the gate of a house is opened in an old documentation,...
This circuit allows you to modify the resolution of a measurement bridge. It was found in the...