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.
This touch sensor, found in an American documentation on transistors, has gained 8 million times...
The block shown in the figure is a basic source with a configuration widely used in technical...
The output of this circuit must be connected to the input of an audio amplifier. The microphone is a small...