This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset current setting. The configuration can be adapted to operate with modern equivalent components.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...