This static switch circuit appears elsewhere on this site from other sources. This was obtained from a Motorola documentation for 1968 power circuits. The Triac can be another according to the load.
This circuit is suitable for low impedance m icrophones. Gain is given by the 2M2 resistor. This...
This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and...
This preamp with several inputs using germanium transistors from the time was found in Japanese...