With this circuit it is possible to connect a comparator to a power stage via two wires. The circuit can be used as a voltage monitor, for example.
This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset...
The purpose of this 1-transistor amplifier is to allow the use of a milliammeter in an application...
We found this circuit in an old General Electric documentation. In fact, PUTs are not common...