This circuit was obtained from a 1965 General Electric SCR manual. The components are from the period.
For an 8 ohm load, this Motorola circuit was found in a 1968 documentation. The transistors are of the time...
This circuit was found in the 1994 Linear Application Handbook by National Semiconductor. The...
This circuit was obtained in the Audio Handbook of the National Semiconductor of 1977. The...