The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and 2N2431 can be used. The circuit is from the 80's and makes use of transformers.
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...