This circuit from a 1970s General Electric publication applies to motors of the series winding type. SCRs support current equivalents and must be equipped with heat sinks.
This circuit was found in an Electronic Design from 1967. The circuit uses two triacs being T2...
Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz...
This shield from the 60's uses a germanium transistor of the time and a common type of relay of...