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 circuit indicates the logical level of a CMOS circuit, extracting the power from the circuit...
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...
The figure shows how to use an oscilloscope for diode test. The circuit presents the...