In this National Semiconductor circuit, the output voltage is numerically equal to the square root of the input voltage. The circuit is from the 90s and the components are from the period.
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...