This circuit is from the Motorola Linear Databook of 1990 and can be implemented with other operational amplifiers. The power supply must be symmetrical.
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...