This vibrato circuit was found in Motorola's 1966 documentation. The circuit uses transistors of the time that can be replaced with current common types. Power is done with 3 9V batteries.
The frequency of the sound emitted by this circuit depends on the light intensity on the sensor....
This circuit is from a thyristor manual from On Semiconductor. It makes use of a PUT and a SCR...
This circuit uses only one NC75Z04 port from ON Semiconductor, but it can be implemented with...