This circuit has a 2 V full scale using a 4-and-a-half-digit A / D converter. The circuit is powered by a voltage of 9 V. We found this configuration in the 1983 Intersil Databook.
This shield, found in old English documentation, appears with variations elsewhere in this section...
This complementary or bilateral emitter follower was found in American documentation from the 90s....
This configuration that functions as a zener diode was found in an English publication from 1976....