We found this circuit in an American documentation from 1947. The circuit uses 5 tubes and has a feature to keep the tube filaments preheated.
This operational amplifier configuration has gain controlled by an external voltage applied to a...
This circuit is from a 1978 publication, being connected to the contact breaker of cars that still...
January 2017 - STMicroelectronics' new TN4015H SCRs with 40 A currents and high temperature...