This circuit is from a factory manual from the 80s. The circuit can be implemented with modern operationals. The supply must be symmetrical, and the diode is general-purpose.
This configuration is from a 1987 publication, but it can be easily assembled today, as the...
This is a simple source indicated for powering low voltage projects on the bench. The circuit is...
This circuit is from Philips' 70s documentation. Transistors can be replaced by modern...