This circuit is from documentation from 1965 but can be easily implemented today using modern transistors. We can use BD136 for Q1 and TIP42 for Q2. The TIP must be equipped with a heat sink.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...