This circuit is from a 1965 Motorola manual. It can be implemented with a common 2N2646 and a 106 Series SCR without problems. The pulse transformer has a 1: 1 turn ratio.
This circuit was found in Motorola documentation from the 1980s. PUTs are not common components...
This low distortion circuit was found in a 1964 Electronic Design. The transistor admits...
This circuit is based on an uncommon Texas component today, as found in an American 1980s...