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.

Simple 1 Transistor Shield (CB15480E)
The circuit, shown in the figure, activates a relay when the logic level applied to its input, from...
TDA2870 10 W amplifier (CB10804E)
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...
Precision Comparator using Photodiodes (CB4947E)
This circuit makes use of the LM11, 112 or 113 operatives and was found in a 1980s documentation. The...