This circuit is from American documentation from the 1980s. The circuit can make use of any common NPN transistor and the power comes from two small batteries.
We find this circuit in a 1980s documentation. The integrated circuit used is unusual today. The...
This high voltage stage has a behavior like to a 12AU7 tube according to the 1975 publication. The transistors...
The circuit with a common operational amplifier uses a zener as a reference. The circuit is from...