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.

Color organ (CB9089E)
This was the original title given by the publication of the 80s in which we found it. Similar...
Video switch (CB8740E)
This circuit for analog video signals was found in a 90s 303 Circuits. The used digital switch is...
Trill Generator (CB21241E)
This circuit mimics the trill of a bird. We found it in an American documentation from the 90s. It is...