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.

Triac high voltage generator (CB8477E)
This UHV generator circuit or ultra-high voltage was found in a 90s Electronic Engineering 90s. The triac...
Pendulum Alarm (CB509)
When the sensor is activated the relay turns on powering na external load such as a buzzer siren...
Transistor Radio GE675 and 676 (CB18441E)
This transistorized receiver was manufactured in the 1960s and distributed worldwide. The diagram is...