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.

Breathalyzer (CB25160E)
This circuit was published in an article in Radio Electronics magazine in October 1988. It uses...
Thermostat with Trigger (CB923E)
This circuit was obtained in an old English magazine (TSI) 1998 and consists of a Schmitt trigger...
Alternating Light Flasher (CB12704E)
The circuit in the figure causes two lamps to flash alternately at a frequency that can be...