Found in a 1968 Texas Instruments documentation this circuit uses an SCR from that time. Modern equivalent types can be used for a higher power version.
Found in a 1970 documentation, this SCR bistable can be implemented with modern equivalent SCRs. Observe...
This circuit must have its input connected to the collector of the last IF transistor of the FM...
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...