This circuit with the HA2400 was found in the March 1980 Radio Electronics magazine. The circuit has digital-gain control and must be powered by a symmetrical 15 V source.
This circuit is from a 1965 General Electric Hobby manual. The circuit uses only passive...
We found this circuit in a 1967 RCA SCR manual. The circuit uses components from the era. The...
Found in American documentation from the 1970s, this circuit can be designed based on a modern SCR,...