Voltage amplifier with the 37 tube (T392E)

Found in a modern design book with tubes, this stage with the triode 37 has a plate current of 3.7 mA.

Highest Current Capacity Voltage Changer LM3900 (CB15992E)
The circuit in the figure has the same purpose as the previous one (CBV15991E), except that it has a...
Complete Cell Protection System (CB5414E)
This complete single cell protection system is suggested by Linear Technology in its 2005 manual....
Slow scan analyzer (CB4174E)
This circuit of an ancient American documentation is intended for cathode ray display analysis of low...