Found in a 1964 Electronic Design, this circuit suppresses arcs that occur in contacts when a relay switches inductive loads.
This alarm, from a 1996 magazine, can be fitted with two BC548s in the original configuration...
In the figure we show how to use a small Hartley oscillator as a continuity tester. The component...
The transistors in this circuit from an old documentation can be replaced by equivalents like the...