We found this circuit in a 1971 documentation. The circuit can be assembled with more modern transistors such as BC548 for Q1, BC558 for Q2 and BD135 for Q3.
This 1998 circuit controls the volume in a stereo system by touching switches. The circuit is for...
This circuit, from a 1974 publication, can be assembled with BC548 transistors. If powered with 6 or...
Found in ancient documentation, this circuit uses a high voltage transistor of the time. Observe...