This high impedance amplifier is from 1985 documentation by General Electronic. The amplifier with FET at the entrance is from the period and the source is 9 V.
This version is one of many that can be found on our website. We found it in Radio Electronics from the...
This circuit for common analog telephones was found in March 1982 Radio Electronics magazine. It...
Figure bellow shows how the 4510, a divide-by-1U, up/down counter with three-state outputs is...