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.
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...