Found in Popular Electronics from the 90s, this circuit uses a reed switch on the rails as a sensor. Instead of lamps, in a modern version, LEDs can be used.
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...