This bargraph circuit is from an ancient American documentation. It indicates the charge state of a set of 4 batteries from 9.6 to 5.2 V.
The purpose of this circuit is to improve the reception of signals from the short-wave band. The...
This highly sensitive light sensor was found in a 1970 General Electric documentation. The circuit...
This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is...