This circuit was found in an ancient American documentation. The power supply is not given, but we have the voltages used. The relay is sensitive type for high voltage.
In the figure we have a typical polarization circuit for MOSFETs with a high impedance...
Obtained in an American documentation from 1976, this circuit has a constant current source for...
This circuit is from a documentation from the 60s. The circuit can be built with transistors like...