Found in an Electronic Engineering from the 80's, this circuit makes use of components of the time. The circuit can be implemented with modern equivalent components.
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...