Found in American documentation from the 90s, this circuit can be used as a shield with the replacement of the output optical coupler. The operational also admits equivalent.
The purpose of this 1-transistor amplifier is to allow the use of a milliammeter in an application...
This circuit causes one LED to light up if the voltage falls below the value set in R3 and the...
This circuit was found in a 1986 documentation and it may be difficult to obtain some of its...