We found this circuit in the 1983 edition of the Electronics Experimenter handbook. The circuit uses components that are common today, although many admit equivalents.
This circuit causes the relay to be energized when the input voltage exceeds the voltage value of...
The circuit we present is suggested by Linear Technologies (www.linear.com) and makes use of an...
Found in American documentation from the 90s, this circuit can be used as a shield with the...